refactor update backend to host-managed PDC pipeline

.github/workflows/release.yml

@@ -317,96 +317,19 @@ jobs:
           Write-Host "Installer size: $([Math]::Round($installerFile.Length / 1MB, 2)) MB"
         shell: pwsh
 
-      - name: Build Signed FileMap Update Package
+      - name: Upload App Payload
-        if: matrix.self_contained == true
-        run: |
-          $ErrorActionPreference = "Stop"
-
-          $version = "${{ needs.prepare.outputs.version }}"
-          $arch = "${{ matrix.arch }}"
-          $platform = "windows-$arch"
-          $publishDir = "publish/windows-$arch"
-          $appDir = "app-$version"
-          $currentAppPath = Join-Path $publishDir $appDir
-          $outputDir = Join-Path "delta-output" $platform
-          $generateScript = "scripts/Generate-DeltaPackage.ps1"
-          $signScript = "scripts/Sign-FileMap.ps1"
-
-          if (-not (Test-Path $currentAppPath)) {
-            Write-Error "Expected app directory not found: $currentAppPath"
-            exit 1
-          }
-
-          New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
-          & $generateScript `
-            -PreviousVersion "0.0.0" `
-            -CurrentVersion $version `
-            -PreviousDir $currentAppPath `
-            -CurrentDir $currentAppPath `
-            -OutputDir $outputDir
-
-          $privateKeyPem = @'
-          ${{ secrets.PDC_SIGNING_KEY }}
-          '@.Trim()
-          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
-            $privateKeyPem = @'
-          ${{ secrets.UPDATE_PRIVATE_KEY_PEM }}
-          '@.Trim()
-          }
-          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
-            Write-Error "Missing required secret: PDC_SIGNING_KEY or UPDATE_PRIVATE_KEY_PEM"
-            exit 1
-          }
-
-          $privateKeyPem = $privateKeyPem -replace '\\n', "`n"
-          $tempDir = Join-Path $env:RUNNER_TEMP "update-signing"
-          New-Item -ItemType Directory -Path $tempDir -Force | Out-Null
-
-          $privateKeyPath = Join-Path $tempDir "private-key.pem"
-          $publicKeyPath = Join-Path $tempDir "public-key.pem"
-
-          Set-Content -Path $privateKeyPath -Value $privateKeyPem -NoNewline
-          $rsa = [System.Security.Cryptography.RSA]::Create()
-          $rsa.ImportFromPem($privateKeyPem)
-          $derivedPublicKey = $rsa.ExportRSAPublicKeyPem()
-          Set-Content -Path $publicKeyPath -Value $derivedPublicKey -NoNewline
-
-          $repoPublicKeyPath = "LanMountainDesktop.Launcher/Assets/public-key.pem"
-          $repoPublicKeyPem = Get-Content -Path $repoPublicKeyPath -Raw
-          $repoRsa = [System.Security.Cryptography.RSA]::Create()
-          $repoRsa.ImportFromPem($repoPublicKeyPem)
-          $repoSpki = [Convert]::ToBase64String($repoRsa.ExportSubjectPublicKeyInfo())
-          $derivedSpki = [Convert]::ToBase64String($rsa.ExportSubjectPublicKeyInfo())
-          if ($repoSpki -ne $derivedSpki) {
-            Write-Error "Configured signing private key does not match $repoPublicKeyPath. Keep keypair consistent before publishing."
-            exit 1
-          }
-
-          & $signScript `
-            -FilesJsonPath (Join-Path $outputDir "files.json") `
-            -PrivateKeyPath $privateKeyPath `
-            -OutputPath (Join-Path $outputDir "files.json.sig")
-
-          Copy-Item (Join-Path $outputDir "files.json") (Join-Path $outputDir "files-$platform.json") -Force
-          Copy-Item (Join-Path $outputDir "files.json.sig") (Join-Path $outputDir "files-$platform.json.sig") -Force
-          Copy-Item (Join-Path $outputDir "update.zip") (Join-Path $outputDir "update-$platform.zip") -Force
-        shell: pwsh
-
-      - name: Upload Signed FileMap Update Package
-        if: matrix.self_contained == true
         uses: actions/upload-artifact@v4
         with:
-          name: release-update-windows-${{ matrix.arch }}
+          name: app-payload-windows-${{ matrix.arch }}
           path: |
-            delta-output/windows-${{ matrix.arch }}/files-windows-${{ matrix.arch }}.json
+            publish/windows-${{ matrix.arch }}/**
-            delta-output/windows-${{ matrix.arch }}/files-windows-${{ matrix.arch }}.json.sig
-            delta-output/windows-${{ matrix.arch }}/update-windows-${{ matrix.arch }}.zip
           if-no-files-found: error
-          retention-days: 90
+          retention-days: 30
+
       - name: Upload Installer
         uses: actions/upload-artifact@v4
         with:
-          name: release-windows-${{ matrix.arch }}${{ matrix.suffix }}
+          name: installer-windows-${{ matrix.arch }}
           path: build-installer/*.exe
           if-no-files-found: error
           retention-days: 30
@@ -608,94 +531,19 @@ jobs:
             exit 1
           fi
 
-      - name: Build Signed FileMap Update Package
+      - name: Upload App Payload
-        shell: pwsh
-        run: |
-          $ErrorActionPreference = "Stop"
-
-          $version = "${{ needs.prepare.outputs.version }}"
-          $platform = "linux-x64"
-          $publishDir = "publish/linux-x64"
-          $appDir = "app-$version"
-          $currentAppPath = Join-Path $publishDir $appDir
-          $outputDir = Join-Path "delta-output" $platform
-          $generateScript = "scripts/Generate-DeltaPackage.ps1"
-          $signScript = "scripts/Sign-FileMap.ps1"
-
-          if (-not (Test-Path $currentAppPath)) {
-            Write-Error "Expected app directory not found: $currentAppPath"
-            exit 1
-          }
-
-          New-Item -ItemType Directory -Path $outputDir -Force | Out-Null
-          & $generateScript `
-            -PreviousVersion "0.0.0" `
-            -CurrentVersion $version `
-            -PreviousDir $currentAppPath `
-            -CurrentDir $currentAppPath `
-            -OutputDir $outputDir
-
-          $privateKeyPem = @'
-          ${{ secrets.PDC_SIGNING_KEY }}
-          '@.Trim()
-          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
-            $privateKeyPem = @'
-          ${{ secrets.UPDATE_PRIVATE_KEY_PEM }}
-          '@.Trim()
-          }
-          if ([string]::IsNullOrWhiteSpace($privateKeyPem)) {
-            Write-Error "Missing required secret: PDC_SIGNING_KEY or UPDATE_PRIVATE_KEY_PEM"
-            exit 1
-          }
-
-          $privateKeyPem = $privateKeyPem -replace '\\n', "`n"
-          $tempDir = Join-Path $env:RUNNER_TEMP "update-signing"
-          New-Item -ItemType Directory -Path $tempDir -Force | Out-Null
-
-          $privateKeyPath = Join-Path $tempDir "private-key.pem"
-          $publicKeyPath = Join-Path $tempDir "public-key.pem"
-
-          Set-Content -Path $privateKeyPath -Value $privateKeyPem -NoNewline
-          $rsa = [System.Security.Cryptography.RSA]::Create()
-          $rsa.ImportFromPem($privateKeyPem)
-          $derivedPublicKey = $rsa.ExportRSAPublicKeyPem()
-          Set-Content -Path $publicKeyPath -Value $derivedPublicKey -NoNewline
-
-          $repoPublicKeyPath = "LanMountainDesktop.Launcher/Assets/public-key.pem"
-          $repoPublicKeyPem = Get-Content -Path $repoPublicKeyPath -Raw
-          $repoRsa = [System.Security.Cryptography.RSA]::Create()
-          $repoRsa.ImportFromPem($repoPublicKeyPem)
-          $repoSpki = [Convert]::ToBase64String($repoRsa.ExportSubjectPublicKeyInfo())
-          $derivedSpki = [Convert]::ToBase64String($rsa.ExportSubjectPublicKeyInfo())
-          if ($repoSpki -ne $derivedSpki) {
-            Write-Error "Configured signing private key does not match $repoPublicKeyPath. Keep keypair consistent before publishing."
-            exit 1
-          }
-
-          & $signScript `
-            -FilesJsonPath (Join-Path $outputDir "files.json") `
-            -PrivateKeyPath $privateKeyPath `
-            -OutputPath (Join-Path $outputDir "files.json.sig")
-
-          Copy-Item (Join-Path $outputDir "files.json") (Join-Path $outputDir "files-$platform.json") -Force
-          Copy-Item (Join-Path $outputDir "files.json.sig") (Join-Path $outputDir "files-$platform.json.sig") -Force
-          Copy-Item (Join-Path $outputDir "update.zip") (Join-Path $outputDir "update-$platform.zip") -Force
-
-      - name: Upload Signed FileMap Update Package
         uses: actions/upload-artifact@v4
         with:
-          name: release-update-linux-x64
+          name: app-payload-linux-x64
           path: |
-            delta-output/linux-x64/files-linux-x64.json
+            publish/linux-x64/**
-            delta-output/linux-x64/files-linux-x64.json.sig
-            delta-output/linux-x64/update-linux-x64.zip
           if-no-files-found: error
-          retention-days: 90
+          retention-days: 30
 
-      - name: Upload
+      - name: Upload Installer
         uses: actions/upload-artifact@v4
         with:
-          name: release-linux
+          name: installer-linux-x64
           path: "*.deb"
           if-no-files-found: error
           retention-days: 30
@@ -859,23 +707,185 @@ jobs:
       - name: Upload
         uses: actions/upload-artifact@v4
         with:
-          name: release-macos-${{ matrix.arch }}
+          name: installer-macos-${{ matrix.arch }}
           path: "*.dmg"
           if-no-files-found: error
           retention-days: 30
 
-  github-release:
+  publish-pdc:
     needs: [ prepare, build-windows, build-linux, build-macos ]
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    env:
+      VERSION: ${{ needs.prepare.outputs.version }}
+      PRIMARY_VERSION: ${{ needs.prepare.outputs.version }}
+      PDCC_primaryVersion: ${{ needs.prepare.outputs.version }}
+      PDCC_VERSION: ${{ vars.PDC_CLIENT_VERSION }}
+      PDCC_version: ${{ vars.PDC_CLIENT_VERSION }}
+      S3_ENDPOINT: ${{ vars.S3_ENDPOINT }}
+      S3_BUCKET: ${{ vars.S3_BUCKET }}
+      S3_REGION: ${{ vars.S3_REGION }}
+      PDC_ENDPOINT: ${{ vars.PDC_ENDPOINT }}
+      PDC_TOKEN: ${{ secrets.PDC_TOKEN }}
+      PDC_SIGNING_KEY: ${{ secrets.PDC_SIGNING_KEY }}
+      UPDATE_PRIVATE_KEY_PEM: ${{ secrets.UPDATE_PRIVATE_KEY_PEM }}
+      S3_ACCESS_KEY: ${{ secrets.S3_ACCESS_KEY }}
+      S3_SECRET_KEY: ${{ secrets.S3_SECRET_KEY }}
+      S3_Endpoint: ${{ vars.S3_ENDPOINT }}
+      S3_Bucket: ${{ vars.S3_BUCKET }}
+      S3_Region: ${{ vars.S3_REGION }}
+      PDC_Endpoint: ${{ vars.PDC_ENDPOINT }}
+      PDC_Token: ${{ secrets.PDC_TOKEN }}
+      PDC_SigningKey: ${{ secrets.PDC_SIGNING_KEY }}
+      S3_AccessKey: ${{ secrets.S3_ACCESS_KEY }}
+      S3_SecretKey: ${{ secrets.S3_SECRET_KEY }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          submodules: recursive
+          ref: ${{ needs.prepare.outputs.checkout_ref }}
+
+      - name: Download payload artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: payload-artifacts
+          pattern: app-payload-*
+
+      - name: Download installer artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: installer-artifacts
+          pattern: installer-*
+
+      - name: Prepare PDC environment
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = "Stop"
+
+          if ([string]::IsNullOrWhiteSpace($env:S3_ENDPOINT) -or
+              [string]::IsNullOrWhiteSpace($env:S3_BUCKET) -or
+              [string]::IsNullOrWhiteSpace($env:PDC_ENDPOINT)) {
+            throw "Missing required PDC/S3 variables."
+          }
+
+          if ([string]::IsNullOrWhiteSpace($env:PDC_SIGNING_KEY)) {
+            if ([string]::IsNullOrWhiteSpace($env:UPDATE_PRIVATE_KEY_PEM)) {
+              throw "Missing UPDATE_PRIVATE_KEY_PEM or PDC_SIGNING_KEY."
+            }
+
+            $env:PDC_SIGNING_KEY = $env:UPDATE_PRIVATE_KEY_PEM
+          }
+
+          $workRoot = Join-Path $PWD "pdc-work"
+          if (Test-Path $workRoot) {
+            Remove-Item -LiteralPath $workRoot -Recurse -Force
+          }
+          New-Item -ItemType Directory -Path $workRoot -Force | Out-Null
+
+          $template = Get-Content -Path "phainon.yml" -Raw
+          $resolved = $template `
+            -replace '__FILE_REPO_ROOT__', "$($env:S3_ENDPOINT.TrimEnd('/'))/$($env:S3_BUCKET)/lanmountain/update/repo/" `
+            -replace '__ARCHIVE_ROOT__', "$($env:S3_ENDPOINT.TrimEnd('/'))/$($env:S3_BUCKET)/lanmountain/update/installers/"
+
+          Set-Content -Path (Join-Path $workRoot "phainon.resolved.yml") -Value $resolved -NoNewline
+
+          python3 -m pip install --user --upgrade awscli
+          Add-Content -Path $env:GITHUB_PATH -Value "$HOME/.local/bin"
+
+      - name: Install PDCC
+        shell: pwsh
+        run: |
+          ./scripts/Install-Pdcc.ps1 -Repository "ClassIsland/PhainonDistributionCenter" -OutputDir "./pdcc"
+
+      - name: Publish with PDCC
+        shell: pwsh
+        run: |
+          $ErrorActionPreference = "Stop"
+          $stageRoot = Join-Path $PWD "pdc-stage"
+          $payloadRoot = Join-Path $PWD "payload-artifacts"
+          $installerRoot = Join-Path $PWD "installer-artifacts"
+          $outRoot = Join-Path $PWD "pdc-output"
+          $client = Join-Path $PWD "pdcc/PhainonDistributionCenter.Client"
+          $config = Join-Path $PWD "pdc-work/phainon.resolved.yml"
+
+          if (Test-Path $stageRoot) {
+            Remove-Item -LiteralPath $stageRoot -Recurse -Force
+          }
+          if (Test-Path $outRoot) {
+            Remove-Item -LiteralPath $outRoot -Recurse -Force
+          }
+          New-Item -ItemType Directory -Path $stageRoot -Force | Out-Null
+          New-Item -ItemType Directory -Path $outRoot -Force | Out-Null
+
+          $payloadArtifacts = Get-ChildItem -LiteralPath $payloadRoot -Directory
+          if (-not $payloadArtifacts) {
+            throw "No payload artifacts were downloaded."
+          }
+
+          $installerArtifacts = Get-ChildItem -LiteralPath $installerRoot -Directory
+          if (-not $installerArtifacts) {
+            throw "No installer artifacts were downloaded."
+          }
+
+          foreach ($installerArtifact in $installerArtifacts) {
+            $stagedInstallerDir = Join-Path $stageRoot "installers/$($installerArtifact.Name)"
+            ./scripts/Prepare-PdccOut.ps1 -SourceDir $installerArtifact.FullName -OutputDir $stagedInstallerDir
+          }
+
+          foreach ($payloadArtifact in $payloadArtifacts) {
+            $platformKey = $payloadArtifact.Name -replace '^app-payload-', ''
+            $stagedPayloadDir = Join-Path $stageRoot "payloads/$platformKey"
+            ./scripts/Prepare-PdccOut.ps1 -SourceDir $payloadArtifact.FullName -OutputDir $stagedPayloadDir
+
+            $subChannel = ($platformKey -replace '-', '_') + "_release_folderClassic"
+            $env:PDC_SUBCHANNEL = $subChannel
+
+            Push-Location $stagedPayloadDir
+            try {
+              & $client $config Publish $env:PRIMARY_VERSION $env:VERSION (Join-Path $outRoot "published/$platformKey")
+              if ($LASTEXITCODE -ne 0) {
+                throw "PDCC Publish failed for $platformKey."
+              }
+            }
+            finally {
+              Pop-Location
+            }
+          }
+
+          if (Test-Path (Join-Path $stageRoot "installers")) {
+            aws --endpoint-url "$env:S3_ENDPOINT" s3 sync (Join-Path $stageRoot "installers") "s3://$env:S3_BUCKET/lanmountain/update/installers/" --only-show-errors
+          }
+
+      - name: Upload PDC Assets
+        uses: actions/upload-artifact@v4
+        with:
+          name: pdc-assets
+          path: |
+            pdc-output/published/**
+          if-no-files-found: error
+          retention-days: 90
+
+  github-release:
+    needs: [ prepare, build-windows, build-linux, build-macos, publish-pdc ]
+    runs-on: ubuntu-latest
     permissions:
       contents: write
 
     steps:
-      - name: Download artifacts
+      - name: Download installer artifacts
         uses: actions/download-artifact@v4
         with:
-          path: artifacts
+          path: artifacts/installers
-          pattern: release-*
+          pattern: installer-*
+
+      - name: Download PDC artifacts
+        uses: actions/download-artifact@v4
+        with:
+          path: artifacts/pdc
+          pattern: pdc-assets
 
       - name: List artifacts structure
         run: |
@@ -892,10 +902,8 @@ jobs:
         run: |
           echo "Organizing artifacts..."
           mkdir -p release-files
-          # Copy installers and packages
+          find artifacts/installers -type f \( -name "*.exe" -o -name "*.deb" -o -name "*.dmg" \) -exec cp -v {} release-files/ \;
-          find artifacts -type f \( -name "*.exe" -o -name "*.deb" -o -name "*.dmg" \) -exec cp -v {} release-files/ \;
+          find artifacts/pdc -type f \( -name "files-*.json" -o -name "files-*.json.sig" -o -name "update-*.zip" \) -exec cp -v {} release-files/ \;
-          # Copy signed file-map incremental update assets
-          find artifacts -type f \( -name "files-*.json" -o -name "files-*.json.sig" -o -name "update-*.zip" \) -exec cp -v {} release-files/ \;
           echo ""
           echo "Files ready for release:"
           ls -lh release-files/ || echo "No files found in release-files"
@@ -908,44 +916,6 @@ jobs:
             exit 1
           fi
 
-      - name: Upload Incremental Assets to S3 (optional)
-        if: ${{ vars.S3_ENDPOINT != '' && vars.S3_BUCKET != '' }}
-        env:
-          S3_ENDPOINT: ${{ vars.S3_ENDPOINT }}
-          S3_BUCKET: ${{ vars.S3_BUCKET }}
-          S3_REGION: ${{ vars.S3_REGION != '' && vars.S3_REGION || 'cn-nb1' }}
-          S3_ACCESS_KEY: ${{ secrets.S3_ACCESS_KEY }}
-          S3_SECRET_KEY: ${{ secrets.S3_SECRET_KEY }}
-          S3_OBJECT_PREFIX: lanmountain/distribution-v1
-        run: |
-          set -euo pipefail
-
-          if [ -z "${S3_ACCESS_KEY:-}" ] || [ -z "${S3_SECRET_KEY:-}" ]; then
-            echo "S3 credentials are not configured. Skipping optional S3 upload step."
-            exit 0
-          fi
-
-          python3 -m pip install --upgrade awscli
-
-          mkdir -p release-update-assets
-          find release-files -type f \( -name "files-*.json" -o -name "files-*.json.sig" -o -name "update-*.zip" \) -exec cp -v {} release-update-assets/ \;
-
-          asset_count=$(find release-update-assets -type f | wc -l)
-          if [ "$asset_count" -eq 0 ]; then
-            echo "Error: no incremental update assets found for S3 upload."
-            exit 1
-          fi
-
-          export AWS_ACCESS_KEY_ID="$S3_ACCESS_KEY"
-          export AWS_SECRET_ACCESS_KEY="$S3_SECRET_KEY"
-          export AWS_DEFAULT_REGION="$S3_REGION"
-
-          version_prefix="${S3_OBJECT_PREFIX}/${{ needs.prepare.outputs.version }}/"
-          latest_prefix="${S3_OBJECT_PREFIX}/latest/"
-
-          aws --endpoint-url "$S3_ENDPOINT" s3 sync release-update-assets "s3://${S3_BUCKET}/${version_prefix}" --only-show-errors
-          aws --endpoint-url "$S3_ENDPOINT" s3 sync release-update-assets "s3://${S3_BUCKET}/${latest_prefix}" --delete --only-show-errors
-
       - name: Create Release
         uses: ncipollo/release-action@v1
         with:

.trae/specs/pdc-incremental-migration/checklist.md

@@ -1,10 +1,13 @@
 # Checklist
 
-- [x] `release.yml` produces signed FileMap incremental assets for Windows x64/x86 and Linux x64.
+- [ ] `release.yml` includes PDCC publish flow and does not invoke Velopack.
-- [x] `release.yml` no longer depends on `vpk`/VeloPack packaging.
+- [ ] `release.yml` uploads app payload artifacts for PDCC.
-- [x] Launcher update engine applies only signed FileMap payload path.
+- [ ] S3 output path is rooted at `lanmountain/update/` (no system version prefix).
-- [x] Host update workflow no longer expects `releases.win.json`/`*.nupkg`.
+- [ ] S3 has `repo/`, `meta/`, and `installers/` outputs after a release run.
-- [x] Update source setting includes `pdc` and preserves GitHub fallback behavior.
+- [ ] Host update source default is `stcn` and old `pdc` values are auto-normalized.
+- [ ] Host can persist PDC payload into launcher incoming directory.
+- [ ] Launcher can apply PDC FileMap payload with signature/hash verification.
+- [ ] Legacy signed `files.json + update.zip` path still works as compatibility fallback.
 - [ ] CI run attached proving all release matrix jobs pass.
 - [ ] N-1 -> N incremental update verified on Windows x64/x86 and Linux x64.
 - [ ] Rollback verification report attached.

.trae/specs/pdc-incremental-migration/spec.md

@@ -2,29 +2,43 @@
 
 ## Goal
 
-Replace VeloPack-based incremental packaging with a unified signed FileMap pipeline and prepare for PDC/S3 distribution compatibility, while keeping Launcher installation, rollback, and update orchestration ownership unchanged.
+Replace VeloPack-based incremental packaging with a unified PDC FileMap + object-repo pipeline, while keeping Launcher installation, rollback, and update orchestration ownership unchanged.
 
-## Stage 1 (Completed in this round)
+## Stage 1 (Completed)
 
-- Release workflow outputs signed FileMap incremental assets as the primary path:
+- Release workflow removed VeloPack-based release packaging.
-  - `files-windows-x64.json` / `.sig` / `update-windows-x64.zip`
+- Signed FileMap path was restored as an interim release mechanism.
-  - `files-windows-x86.json` / `.sig` / `update-windows-x86.zip`
+- Host/Launcher fallback behavior stayed compatible with `files.json + files.json.sig + update.zip`.
-  - `files-linux-x64.json` / `.sig` / `update-linux-x64.zip`
-- Launcher and host update runtime remove VeloPack branches and return to signed FileMap apply path.
-- Host update asset discovery supports platform-scoped names with fallback to legacy generic names.
-- Optional S3 sync publishes incremental assets in parallel with GitHub Release assets.
 
-## Stage 2 (In Progress)
+## Stage 2 (Current Implementation Target)
 
-- Introduce PDC-compatible update source (`pdc`) with fallback to GitHub.
+- Move release publishing to PDCC + `phainon.yml` (ClassIsland-style).
-- Add PDC metadata/latest/distribution API consumption abstraction.
+- Promote PDC-distributed FileMap/object-repo as the primary incremental path.
-- Keep Launcher install/apply/rollback state machine unchanged.
+- Keep GitHub Release installers and metadata as parallel distribution.
-- Prepare `phainon.yml`-compatible release metadata for future PDCC integration.
+- Keep Launcher state machine ownership (`.current/.partial/.destroy` + snapshots).
+- Update source defaults to `stcn` (S3/PDC), with GitHub fallback.
+- S3 object root is fixed to `lanmountain/update/` with no update-system version prefix.
+
+Expected S3 layout:
+  - `lanmountain/update/repo/<hash-prefix>/<hash-object>`
+  - `lanmountain/update/meta/channels/<channel>/<subchannel>/latest.json`
+  - `lanmountain/update/meta/distributions/<distributionId>/*.json`
+  - `lanmountain/update/installers/<platform>/<arch>/*`
 
 ## Acceptance
 
-- `release.yml` no longer contains VeloPack packaging steps.
+- `release.yml` includes PDCC publish steps and no Velopack steps.
-- Windows x64/x86 and Linux x64 release jobs all upload signed FileMap incremental assets.
+- Release jobs keep building installers for Windows x64/x86, Linux x64, and macOS.
-- Host auto-update can detect and download platform-matching signed FileMap assets.
+- PDC metadata + FileMap + object repo are published under `lanmountain/update/`.
-- Launcher `update apply` succeeds with signed FileMap payload and rollback behavior remains unchanged.
+- Host can consume PDC payload (`stcn` source) and fallback to GitHub when unavailable.
-- Optional S3 upload step works when S3 secrets/vars are configured.
+- Launcher can apply both:
+  - legacy signed `files.json + update.zip`
+  - PDC FileMap object-repo payload.
+- Rollback semantics remain unchanged.
+
+## Deprecated Notes
+
+- The following interim outputs are compatibility-only (not the long-term primary path):
+  - `files-windows-x64.json` / `.sig` / `update-windows-x64.zip`
+  - `files-windows-x86.json` / `.sig` / `update-windows-x86.zip`
+  - `files-linux-x64.json` / `.sig` / `update-linux-x64.zip`

.trae/specs/pdc-incremental-migration/tasks.md

@@ -1,12 +1,15 @@
 # Tasks
 
 - [x] Remove VeloPack packaging from release workflow.
-- [x] Promote signed FileMap generation to release primary path.
+- [x] Keep signed FileMap path as interim compatibility fallback.
-- [x] Output platform-scoped incremental assets for Windows x64/x86 and Linux x64.
+- [x] Remove launcher/runtime Velopack branching.
-- [x] Remove launcher/runtime VeloPack branches.
+- [ ] Add `phainon.yml` for PDCC publish configuration.
-- [x] Update host asset discovery to platform-scoped signed FileMap naming.
+- [ ] Add PDCC installation + publish steps in `release.yml`.
-- [x] Add optional S3 sync for incremental assets.
+- [ ] Upload app payload artifacts for PDCC consumption in release build jobs.
-- [x] Extend update source values with `pdc`.
+- [ ] Publish PDC metadata + object repo to S3 path root `lanmountain/update/`.
-- [x] Add PDC check fallback service skeleton in settings domain.
+- [ ] Mirror installers to `lanmountain/update/installers/<platform>/<arch>/`.
-- [ ] Add full PDC FileMap object-hash download/deploy path.
+- [ ] Replace update source canonical value with `stcn` (keep legacy `pdc` compatibility).
-- [ ] Add PDCC publish integration and `phainon.yml` CI publishing flow.
+- [ ] Add PDC payload model into host update check result.
+- [ ] Add host download path for PDC payload (`pdc-filemap.json` + signature + metadata).
+- [ ] Add launcher PDC FileMap apply path with rollback-compatible semantics.
+- [ ] Keep old `files.json + update.zip` path behind compatibility fallback.

LanMountainDesktop.Launcher/App.axaml.cs

@@ -214,14 +214,12 @@ public partial class App : Application
             var deploymentLocator = new DeploymentLocator(appRoot);
             
             // TODO: 从配置读取 GitHub 仓库信息
-            var updateCheckService = new UpdateCheckService("ClassIsland", "LanMountainDesktop");
             
             coordinator = new LauncherFlowCoordinator(
                 context,
                 deploymentLocator,
                 new OobeStateService(appRoot),
                 new UpdateEngineService(deploymentLocator),
-                updateCheckService,
                 new PluginInstallerService());
 
             result = await coordinator.RunAsync(splashWindow).ConfigureAwait(false);

LanMountainDesktop.Launcher/AppJsonContext.cs

@@ -9,6 +9,11 @@ namespace LanMountainDesktop.Launcher;
 [JsonSourceGenerationOptions(WriteIndented = true, PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase)]
 [JsonSerializable(typeof(SignedFileMap))]
 [JsonSerializable(typeof(UpdateFileEntry))]
+[JsonSerializable(typeof(PdcUpdateMetadata))]
+[JsonSerializable(typeof(PdcFileMap))]
+[JsonSerializable(typeof(PdcComponentEntry))]
+[JsonSerializable(typeof(PdcFileEntry))]
+[JsonSerializable(typeof(PdcHashDescriptor))]
 [JsonSerializable(typeof(SnapshotMetadata))]
 [JsonSerializable(typeof(AppVersionInfo))]
 [JsonSerializable(typeof(StartupProgressMessage))]

LanMountainDesktop.Launcher/Models/UpdateModels.cs

@@ -53,3 +53,92 @@ internal sealed class UpdateApplyResult
 
     public string? RolledBackTo { get; init; }
 }
+
+internal sealed class PdcUpdateMetadata
+{
+    public string? DistributionId { get; set; }
+
+    public string? Channel { get; set; }
+
+    public string? SubChannel { get; set; }
+
+    public string? FromVersion { get; set; }
+
+    public string? ToVersion { get; set; }
+
+    public string? FileMapPath { get; set; }
+
+    public string? FileMapSignaturePath { get; set; }
+
+    public Dictionary<string, string> Metadata { get; set; } = [];
+}
+
+internal sealed class PdcFileMap
+{
+    public string? DistributionId { get; set; }
+
+    public string? FromVersion { get; set; }
+
+    public string? ToVersion { get; set; }
+
+    public string? Version { get; set; }
+
+    public string? Platform { get; set; }
+
+    public string? Arch { get; set; }
+
+    public Dictionary<string, string> Metadata { get; set; } = [];
+
+    public List<PdcComponentEntry> Components { get; set; } = [];
+
+    public List<PdcFileEntry> Files { get; set; } = [];
+}
+
+internal sealed class PdcComponentEntry
+{
+    public string Name { get; set; } = string.Empty;
+
+    public string? Version { get; set; }
+
+    public Dictionary<string, string> Metadata { get; set; } = [];
+
+    public List<PdcFileEntry> Files { get; set; } = [];
+}
+
+internal sealed class PdcFileEntry
+{
+    public string Path { get; set; } = string.Empty;
+
+    public string? Action { get; set; } = "replace";
+
+    public string? Url { get; set; }
+
+    public string? ObjectUrl { get; set; }
+
+    public string? ObjectPath { get; set; }
+
+    public string? ObjectKey { get; set; }
+
+    public string? ArchivePath { get; set; }
+
+    public string? Sha256 { get; set; }
+
+    public string? Sha512 { get; set; }
+
+    public string? Sha512Base64 { get; set; }
+
+    public byte[]? Sha512Bytes { get; set; }
+
+    public PdcHashDescriptor? Hash { get; set; }
+
+    public Dictionary<string, string> Metadata { get; set; } = [];
+}
+
+internal sealed class PdcHashDescriptor
+{
+    public string? Algorithm { get; set; }
+
+    public string? Value { get; set; }
+
+    public byte[]? Bytes { get; set; }
+}

LanMountainDesktop.Launcher/Services/LauncherFlowCoordinator.cs

@@ -22,7 +22,6 @@ internal sealed class LauncherFlowCoordinator
     private readonly DeploymentLocator _deploymentLocator;
     private readonly OobeStateService _oobeStateService;
     private readonly UpdateEngineService _updateEngine;
-    private readonly UpdateCheckService _updateCheckService;
     private readonly PluginInstallerService _pluginInstallerService;
     private readonly IReadOnlyList<IOobeStep> _oobeSteps;
 
@@ -31,14 +30,12 @@ internal sealed class LauncherFlowCoordinator
         DeploymentLocator deploymentLocator,
         OobeStateService oobeStateService,
         UpdateEngineService updateEngine,
-        UpdateCheckService updateCheckService,
         PluginInstallerService pluginInstallerService)
     {
         _context = context;
         _deploymentLocator = deploymentLocator;
         _oobeStateService = oobeStateService;
         _updateEngine = updateEngine;
-        _updateCheckService = updateCheckService;
         _pluginInstallerService = pluginInstallerService;
         _oobeSteps = [new WelcomeOobeStep(_oobeStateService)];
     }

LanMountainDesktop/Models/AppSettingsSnapshot.cs

@@ -85,7 +85,7 @@ public sealed class AppSettingsSnapshot
 
     public string UpdateMode { get; set; } = "download_then_confirm";
 
-    public string UpdateDownloadSource { get; set; } = "pdc";
+    public string UpdateDownloadSource { get; set; } = "stcn";
 
     public int UpdateDownloadThreads { get; set; } = 4;
 

LanMountainDesktop/Services/GitHubReleaseUpdateService.cs

@@ -34,7 +34,17 @@ public sealed record UpdateCheckResult(
     GitHubReleaseInfo? Release,
     GitHubReleaseAsset? PreferredAsset,
     string? ErrorMessage,
-    bool ForceMode = false);
+    bool ForceMode = false,
+    PdcUpdatePayload? PdcPayload = null);
+
+public sealed record PdcUpdatePayload(
+    string DistributionId,
+    string ChannelId,
+    string SubChannel,
+    string? FileMapJson,
+    string? FileMapSignature,
+    string? FileMapJsonUrl,
+    string? FileMapSignatureUrl);
 
 public sealed record UpdateDownloadResult(
     bool Success,

LanMountainDesktop/Services/PdcReleaseUpdateService.cs

@@ -148,7 +148,8 @@ public sealed class PdcReleaseUpdateService : IDisposable
             var distributionNode = await GetContentNodeAsync(distributionUrl, cancellationToken).ConfigureAwait(false);
 
             var assets = ResolveAssets(distributionNode);
-            if (assets.Count == 0)
+            var pdcPayload = ResolvePdcPayload(distributionNode, distributionId, channelId, subChannel);
+            if (assets.Count == 0 && !HasPdcPayload(pdcPayload))
             {
                 return new UpdateCheckResult(
                     Success: false,
@@ -168,6 +169,7 @@ public sealed class PdcReleaseUpdateService : IDisposable
                 IsDraft: false,
                 PublishedAt: DateTimeOffset.UtcNow,
                 Assets: assets);
+            var preferredAsset = SelectPreferredInstallerAsset(assets);
 
             return new UpdateCheckResult(
                 Success: true,
@@ -175,9 +177,10 @@ public sealed class PdcReleaseUpdateService : IDisposable
                 CurrentVersionText: normalizedCurrentVersionText,
                 LatestVersionText: latestVersionText,
                 Release: release,
-                PreferredAsset: null,
+                PreferredAsset: preferredAsset,
                 ErrorMessage: null,
-                ForceMode: isForce);
+                ForceMode: isForce,
+                PdcPayload: pdcPayload);
         }
         catch (OperationCanceledException)
         {
@@ -289,6 +292,119 @@ public sealed class PdcReleaseUpdateService : IDisposable
         return assets;
     }
 
+    private static PdcUpdatePayload ResolvePdcPayload(
+        JsonElement distributionNode,
+        string distributionId,
+        string channelId,
+        string subChannel)
+    {
+        var fileMapJson = ReadString(distributionNode, "fileMapJson");
+        var fileMapSignature = ReadString(distributionNode, "fileMapSignature");
+        var fileMapJsonUrl = ReadString(distributionNode, "fileMapJsonUrl")
+                             ?? ReadString(distributionNode, "fileMapUrl")
+                             ?? ReadString(distributionNode, "manifestUrl");
+        var fileMapSignatureUrl = ReadString(distributionNode, "fileMapSignatureUrl")
+                                  ?? ReadString(distributionNode, "signatureUrl");
+        return new PdcUpdatePayload(
+            DistributionId: distributionId,
+            ChannelId: channelId,
+            SubChannel: subChannel,
+            FileMapJson: fileMapJson,
+            FileMapSignature: fileMapSignature,
+            FileMapJsonUrl: fileMapJsonUrl,
+            FileMapSignatureUrl: fileMapSignatureUrl);
+    }
+
+    private static bool HasPdcPayload(PdcUpdatePayload payload)
+    {
+        return !string.IsNullOrWhiteSpace(payload.FileMapJson)
+               || !string.IsNullOrWhiteSpace(payload.FileMapJsonUrl);
+    }
+
+    private static GitHubReleaseAsset? SelectPreferredInstallerAsset(IReadOnlyList<GitHubReleaseAsset> assets)
+    {
+        if (assets is null || assets.Count == 0)
+        {
+            return null;
+        }
+
+        if (OperatingSystem.IsWindows())
+        {
+            var archToken = RuntimeInformation.OSArchitecture switch
+            {
+                Architecture.Arm64 => "arm64",
+                Architecture.X86 => "x86",
+                _ => "x64"
+            };
+            return assets
+                .Select(asset => (Asset: asset, Score: ScoreInstallerAsset(asset.Name, ".exe", ".msi", archToken)))
+                .OrderByDescending(x => x.Score)
+                .FirstOrDefault(x => x.Score > 0)
+                .Asset;
+        }
+
+        if (OperatingSystem.IsLinux())
+        {
+            return assets
+                .Select(asset => (Asset: asset, Score: ScoreInstallerAsset(asset.Name, ".deb", ".rpm", "x64")))
+                .OrderByDescending(x => x.Score)
+                .FirstOrDefault(x => x.Score > 0)
+                .Asset;
+        }
+
+        if (OperatingSystem.IsMacOS())
+        {
+            var archToken = RuntimeInformation.OSArchitecture == Architecture.Arm64 ? "arm64" : "x64";
+            return assets
+                .Select(asset => (Asset: asset, Score: ScoreInstallerAsset(asset.Name, ".dmg", ".pkg", archToken)))
+                .OrderByDescending(x => x.Score)
+                .FirstOrDefault(x => x.Score > 0)
+                .Asset;
+        }
+
+        return null;
+    }
+
+    private static int ScoreInstallerAsset(string name, string ext1, string ext2, string archToken)
+    {
+        if (string.IsNullOrWhiteSpace(name))
+        {
+            return 0;
+        }
+
+        var score = 0;
+        if (name.EndsWith(ext1, StringComparison.OrdinalIgnoreCase))
+        {
+            score += 200;
+        }
+        else if (name.EndsWith(ext2, StringComparison.OrdinalIgnoreCase))
+        {
+            score += 160;
+        }
+        else
+        {
+            return 0;
+        }
+
+        if (name.Contains("setup", StringComparison.OrdinalIgnoreCase) ||
+            name.Contains("installer", StringComparison.OrdinalIgnoreCase))
+        {
+            score += 50;
+        }
+
+        if (name.Contains(archToken, StringComparison.OrdinalIgnoreCase))
+        {
+            score += 40;
+        }
+
+        if (name.Contains("portable", StringComparison.OrdinalIgnoreCase))
+        {
+            score -= 30;
+        }
+
+        return score;
+    }
+
     private static string ResolveChannelId(JsonElement metadataNode, bool includePrerelease)
     {
         if (metadataNode.ValueKind != JsonValueKind.Object ||

LanMountainDesktop/Services/Settings/SettingsContracts.cs

@@ -356,6 +356,7 @@ public interface IUpdateSettingsService
     void Save(UpdateSettingsState state);
     Task<UpdateCheckResult> CheckForUpdatesAsync(Version currentVersion, bool includePrerelease, CancellationToken cancellationToken = default);
     Task<UpdateCheckResult> ForceCheckForUpdatesAsync(Version currentVersion, bool includePrerelease, CancellationToken cancellationToken = default);
+    Task<PdcUpdatePayload?> GetPdcUpdatePayloadAsync(Version currentVersion, bool includePrerelease, bool isForce = false, CancellationToken cancellationToken = default);
     Task<UpdateDownloadResult> DownloadAssetAsync(
         GitHubReleaseAsset asset,
         string destinationFilePath,

LanMountainDesktop/Services/Settings/SettingsDomainServices.cs

@@ -842,6 +842,18 @@ internal sealed class UpdateSettingsService : IUpdateSettingsService, IDisposabl
         return CheckForUpdatesCoreAsync(currentVersion, includePrerelease, isForce: true, cancellationToken);
     }
 
+    public async Task<PdcUpdatePayload?> GetPdcUpdatePayloadAsync(
+        Version currentVersion,
+        bool includePrerelease,
+        bool isForce = false,
+        CancellationToken cancellationToken = default)
+    {
+        var result = isForce
+            ? await _pdcReleaseUpdateService.ForceCheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken)
+            : await _pdcReleaseUpdateService.CheckForUpdatesAsync(currentVersion, includePrerelease, cancellationToken);
+        return result.Success ? result.PdcPayload : null;
+    }
+
     public Task<UpdateDownloadResult> DownloadAssetAsync(
         GitHubReleaseAsset asset,
         string destinationFilePath,

LanMountainDesktop/Services/UpdateSettingsValues.cs

@@ -11,7 +11,10 @@ public static class UpdateSettingsValues
     public const string ModeDownloadThenConfirm = "download_then_confirm";
     public const string ModeSilentOnExit = "silent_on_exit";
 
-    public const string DownloadSourcePdc = "pdc";
+    // NOTE: keep constant name for compatibility with existing call sites.
+    public const string DownloadSourcePdc = "stcn";
+    public const string DownloadSourceStcn = DownloadSourcePdc;
+    public const string LegacyDownloadSourcePdc = "pdc";
     public const string DownloadSourceGitHub = "github";
     public const string DownloadSourceGhProxy = "gh-proxy";
 
@@ -52,6 +55,11 @@ public static class UpdateSettingsValues
 
     public static string NormalizeDownloadSource(string? value)
     {
+        if (string.Equals(value, LegacyDownloadSourcePdc, StringComparison.OrdinalIgnoreCase))
+        {
+            return DownloadSourceStcn;
+        }
+
         if (string.Equals(value, DownloadSourcePdc, StringComparison.OrdinalIgnoreCase))
         {
             return DownloadSourcePdc;
@@ -67,8 +75,8 @@ public static class UpdateSettingsValues
             return DownloadSourceGitHub;
         }
 
-        // Default to PDC. Runtime will fallback to GitHub if PDC is unavailable.
+        // Default to STCN(PDC/S3). Runtime will fallback to GitHub if STCN is unavailable.
-        return DownloadSourcePdc;
+        return DownloadSourceStcn;
     }
 
     public static int NormalizeDownloadThreads(int value)

LanMountainDesktop/Services/UpdateWorkflowService.cs

@@ -5,7 +5,11 @@ using System.Diagnostics;
 using System.Globalization;
 using System.IO;
 using System.Linq;
+using System.Net.Http;
 using System.Runtime.InteropServices;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
 using System.Threading;
 using System.Threading.Tasks;
 using LanMountainDesktop.PluginSdk;
@@ -53,9 +57,20 @@ public sealed class UpdateWorkflowService
     private const string LauncherDirectoryName = ".launcher";
     private const string UpdateDirectoryName = "update";
     private const string IncomingDirectoryName = "incoming";
+    private const string IncomingObjectsDirectoryName = "objects";
     private const string SignedFileMapName = "files.json";
     private const string SignedFileMapSignatureName = "files.json.sig";
     private const string UpdateArchiveName = "update.zip";
+    private const string PdcFileMapName = "pdc-filemap.json";
+    private const string PdcFileMapSignatureName = "pdc-filemap.sig";
+    private const string PdcUpdateStateName = "pdc-update.json";
+
+    private static readonly HttpClient PdcHttpClient = new()
+    {
+        Timeout = TimeSpan.FromMinutes(5)
+    };
+
+    private static readonly ResumableDownloadService PdcDownloadService = new(PdcHttpClient);
 
     public UpdateWorkflowService(ISettingsFacadeService settingsFacade)
     {
@@ -81,6 +96,11 @@ public sealed class UpdateWorkflowService
         return Path.Combine(launcherRoot, LauncherDirectoryName, UpdateDirectoryName, IncomingDirectoryName);
     }
 
+    public static string GetLauncherIncomingObjectsDirectory()
+    {
+        return Path.Combine(GetLauncherIncomingDirectory(), IncomingObjectsDirectoryName);
+    }
+
     /// <summary>
     /// Checks whether a GitHub Release contains signed file-map assets needed for incremental updates.
     /// </summary>
@@ -94,6 +114,16 @@ public sealed class UpdateWorkflowService
         return TryResolveDeltaAssets(release.Assets, out _, out _, out _);
     }
 
+    public static bool IsDeltaUpdateAvailable(UpdateCheckResult checkResult)
+    {
+        if (checkResult.PdcPayload is not null)
+        {
+            return true;
+        }
+
+        return checkResult.Release is not null && IsDeltaUpdateAvailable(checkResult.Release);
+    }
+
     /// <summary>
     /// Downloads signed file-map assets to the Launcher's incoming directory.
     /// </summary>
@@ -104,12 +134,24 @@ public sealed class UpdateWorkflowService
     {
         ArgumentNullException.ThrowIfNull(checkResult);
 
-        if (!checkResult.Success || !checkResult.IsUpdateAvailable || checkResult.Release is null)
+        if (!checkResult.Success || !checkResult.IsUpdateAvailable)
         {
             return new UpdateDownloadResult(false, null, "No update available for delta download.");
         }
 
-        if (!TryResolveDeltaAssets(checkResult.Release.Assets, out var manifestAsset, out var signatureAsset, out var archiveAsset))
+        if (checkResult.PdcPayload is null && checkResult.Release is null)
+        {
+            return new UpdateDownloadResult(false, null, "No update payload is available for delta download.");
+        }
+
+        if (checkResult.PdcPayload is not null)
+        {
+            return await DownloadPdcDeltaUpdateAsync(checkResult, progress, cancellationToken);
+        }
+
+        var release = checkResult.Release;
+        if (release is null ||
+            !TryResolveDeltaAssets(release.Assets, out var manifestAsset, out var signatureAsset, out var archiveAsset))
         {
             return new UpdateDownloadResult(false, null, "Release does not contain compatible signed file-map assets.");
         }
@@ -189,9 +231,9 @@ public sealed class UpdateWorkflowService
         {
             PendingUpdateInstallerPath = Path.Combine(incomingDir, SignedFileMapName),
             PendingUpdateVersion = checkResult.LatestVersionText,
-            PendingUpdatePublishedAtUtcMs = checkResult.Release.PublishedAt == DateTimeOffset.MinValue
+            PendingUpdatePublishedAtUtcMs = checkResult.Release?.PublishedAt is DateTimeOffset publishedAt && publishedAt != DateTimeOffset.MinValue
-                ? null
+                ? publishedAt.ToUnixTimeMilliseconds()
-                : checkResult.Release.PublishedAt.ToUnixTimeMilliseconds(),
+                : null,
             LastUpdateCheckUtcMs = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
             PendingUpdateSha256 = null
         });
@@ -201,6 +243,163 @@ public sealed class UpdateWorkflowService
         return new UpdateDownloadResult(true, Path.Combine(incomingDir, SignedFileMapName), null);
     }
 
+    private async Task<UpdateDownloadResult> DownloadPdcDeltaUpdateAsync(
+        UpdateCheckResult checkResult,
+        IProgress<double>? progress = null,
+        CancellationToken cancellationToken = default)
+    {
+        var payload = checkResult.PdcPayload;
+        if (payload is null)
+        {
+            return new UpdateDownloadResult(false, null, "PDC payload is missing.");
+        }
+
+        var incomingDir = GetLauncherIncomingDirectory();
+        var objectsDir = GetLauncherIncomingObjectsDirectory();
+
+        try
+        {
+            Directory.CreateDirectory(incomingDir);
+            Directory.CreateDirectory(objectsDir);
+        }
+        catch (Exception ex)
+        {
+            return new UpdateDownloadResult(false, null, $"Failed to create incoming directory: {ex.Message}");
+        }
+
+        try
+        {
+            var state = _settingsFacade.Update.Get();
+            var downloadThreads = Math.Max(1, state.UpdateDownloadThreads);
+            var fileMapPath = Path.Combine(incomingDir, PdcFileMapName);
+            var signaturePath = Path.Combine(incomingDir, PdcFileMapSignatureName);
+            var updateStatePath = Path.Combine(incomingDir, PdcUpdateStateName);
+
+            var fileMapJson = await EnsurePdcTextResourceAsync(
+                payload.FileMapJson,
+                payload.FileMapJsonUrl,
+                fileMapPath,
+                cancellationToken);
+
+            var fileMapSignature = await EnsurePdcTextResourceAsync(
+                payload.FileMapSignature,
+                payload.FileMapSignatureUrl,
+                signaturePath,
+                cancellationToken);
+
+            var downloadEntries = ParsePdcDownloadEntries(fileMapJson);
+            if (downloadEntries.Count == 0)
+            {
+                return new UpdateDownloadResult(false, null, "PDC file map does not contain downloadable objects.");
+            }
+
+            var expectedObjectCount = downloadEntries.Count;
+            var completedItems = 2;
+            progress?.Report(expectedObjectCount == 0 ? 1d : (double)completedItems / (expectedObjectCount + 2));
+
+            var objectResults = new List<PdcDownloadedObjectInfo>(expectedObjectCount);
+            var objectTargets = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            var totalSteps = expectedObjectCount + 2;
+
+            foreach (var entry in downloadEntries)
+            {
+                if (!objectTargets.Add(entry.ObjectHashHex))
+                {
+                    completedItems++;
+                    progress?.Report((double)completedItems / totalSteps);
+                    continue;
+                }
+
+                var destinationPath = GetPdcObjectDestinationPath(objectsDir, entry.ObjectHashHex);
+                var destinationDirectory = Path.GetDirectoryName(destinationPath);
+                if (!string.IsNullOrWhiteSpace(destinationDirectory))
+                {
+                    Directory.CreateDirectory(destinationDirectory);
+                }
+
+                if (File.Exists(destinationPath))
+                {
+                    var existingHash = await ComputeFileSha512HexAsync(destinationPath, cancellationToken);
+                    if (string.Equals(existingHash, entry.ObjectHashHex, StringComparison.OrdinalIgnoreCase))
+                    {
+                        objectResults.Add(new PdcDownloadedObjectInfo(entry.ComponentId, entry.RelativePath, entry.DownloadUrl, entry.ObjectHashHex, destinationPath));
+                        completedItems++;
+                        progress?.Report((double)completedItems / totalSteps);
+                        continue;
+                    }
+                }
+
+                var downloadOptions = new DownloadOptions(MaxParallelSegments: downloadThreads);
+                var downloadResult = await PdcDownloadService.DownloadAsync(
+                    entry.DownloadUrl,
+                    destinationPath,
+                    downloadOptions,
+                    null,
+                    cancellationToken);
+
+                if (!downloadResult.Success)
+                {
+                    return new UpdateDownloadResult(false, null, $"Failed to download PDC object {entry.RelativePath}: {downloadResult.ErrorMessage}");
+                }
+
+                var actualHash = await ComputeFileSha512HexAsync(destinationPath, cancellationToken);
+                if (!string.IsNullOrWhiteSpace(actualHash) &&
+                    !string.Equals(actualHash, entry.ObjectHashHex, StringComparison.OrdinalIgnoreCase))
+                {
+                    return new UpdateDownloadResult(false, null, $"PDC object hash mismatch for {entry.RelativePath}. Expected: {entry.ObjectHashHex}, Actual: {actualHash}");
+                }
+
+                objectResults.Add(new PdcDownloadedObjectInfo(entry.ComponentId, entry.RelativePath, entry.DownloadUrl, entry.ObjectHashHex, destinationPath));
+                completedItems++;
+                progress?.Report((double)completedItems / totalSteps);
+            }
+
+            var updateState = new PdcUpdateState(
+                checkResult.LatestVersionText,
+                payload.DistributionId,
+                payload.ChannelId,
+                payload.SubChannel,
+                fileMapPath,
+                signaturePath,
+                objectsDir,
+                DateTimeOffset.UtcNow,
+                fileMapJson,
+                fileMapSignature,
+                objectResults);
+
+            await File.WriteAllTextAsync(updateStatePath, JsonSerializer.Serialize(updateState, UpdateJsonOptions), cancellationToken);
+
+            SaveState(state with
+            {
+                PendingUpdateInstallerPath = updateStatePath,
+                PendingUpdateVersion = checkResult.LatestVersionText,
+                PendingUpdatePublishedAtUtcMs = checkResult.Release?.PublishedAt is DateTimeOffset publishedAt && publishedAt != DateTimeOffset.MinValue
+                    ? publishedAt.ToUnixTimeMilliseconds()
+                    : null,
+                LastUpdateCheckUtcMs = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
+                PendingUpdateSha256 = null
+            });
+
+            progress?.Report(1d);
+            AppLogger.Info("UpdateWorkflow", $"PDC update payload downloaded to {incomingDir}. Will be applied by Launcher on next startup.");
+            return new UpdateDownloadResult(true, updateStatePath, null);
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (Exception ex)
+        {
+            AppLogger.Warn("UpdateWorkflow", "Failed to download PDC incremental payload.", ex);
+            return new UpdateDownloadResult(false, null, ex.Message);
+        }
+    }
+
+    private static readonly JsonSerializerOptions UpdateJsonOptions = new()
+    {
+        WriteIndented = true
+    };
+
     /// <summary>
     /// Checks whether the pending update is managed by Launcher incoming payload.
     /// </summary>
@@ -213,11 +412,261 @@ public sealed class UpdateWorkflowService
             return false;
         }
 
-        // Incoming payload updates are identified by files.json or incoming directory path.
+        // Incoming payload updates are identified by the local manifest or incoming directory path.
         return pendingPath.EndsWith(SignedFileMapName, StringComparison.OrdinalIgnoreCase)
+            || pendingPath.EndsWith(PdcUpdateStateName, StringComparison.OrdinalIgnoreCase)
+            || pendingPath.EndsWith(PdcFileMapName, StringComparison.OrdinalIgnoreCase)
+            || pendingPath.EndsWith(PdcFileMapSignatureName, StringComparison.OrdinalIgnoreCase)
             || pendingPath.Contains(IncomingDirectoryName, StringComparison.OrdinalIgnoreCase);
     }
 
+    private static string GetPdcObjectDestinationPath(string objectsDirectory, string objectHashHex)
+    {
+        var normalizedHash = objectHashHex.Trim().ToLowerInvariant();
+        var shard = normalizedHash.Length >= 2 ? normalizedHash[..2] : normalizedHash;
+        return Path.Combine(objectsDirectory, shard, normalizedHash);
+    }
+
+    private static async Task<string> EnsurePdcTextResourceAsync(
+        string? inlineContent,
+        string? sourceUrl,
+        string destinationPath,
+        CancellationToken cancellationToken)
+    {
+        if (!string.IsNullOrWhiteSpace(inlineContent))
+        {
+            await File.WriteAllTextAsync(destinationPath, inlineContent, cancellationToken);
+            return inlineContent;
+        }
+
+        if (string.IsNullOrWhiteSpace(sourceUrl))
+        {
+            throw new InvalidOperationException("PDC payload does not contain a file map source.");
+        }
+
+        var downloadResult = await PdcDownloadService.DownloadAsync(
+            sourceUrl,
+            destinationPath,
+            cancellationToken: cancellationToken);
+
+        if (!downloadResult.Success)
+        {
+            throw new InvalidOperationException($"Failed to download PDC file map resource: {downloadResult.ErrorMessage}");
+        }
+
+        return await File.ReadAllTextAsync(destinationPath, cancellationToken);
+    }
+
+    private static IReadOnlyList<PdcDownloadEntry> ParsePdcDownloadEntries(string fileMapJson)
+    {
+        var entries = new List<PdcDownloadEntry>();
+        if (string.IsNullOrWhiteSpace(fileMapJson))
+        {
+            return entries;
+        }
+
+        using var document = JsonDocument.Parse(fileMapJson);
+        var root = document.RootElement;
+        if (root.ValueKind != JsonValueKind.Object)
+        {
+            return entries;
+        }
+
+        if (!TryGetPropertyIgnoreCase(root, "components", out var componentsNode) ||
+            componentsNode.ValueKind != JsonValueKind.Object)
+        {
+            return entries;
+        }
+
+        foreach (var component in componentsNode.EnumerateObject())
+        {
+            if (component.Value.ValueKind != JsonValueKind.Object)
+            {
+                continue;
+            }
+
+            if (!TryGetPropertyIgnoreCase(component.Value, "files", out var filesNode) ||
+                filesNode.ValueKind != JsonValueKind.Object)
+            {
+                continue;
+            }
+
+            foreach (var fileEntry in filesNode.EnumerateObject())
+            {
+                if (fileEntry.Value.ValueKind != JsonValueKind.Object)
+                {
+                    continue;
+                }
+
+                var downloadUrl = ReadStringIgnoreCase(fileEntry.Value, "archivedownloadurl")
+                                  ?? ReadStringIgnoreCase(fileEntry.Value, "downloadurl")
+                                  ?? ReadStringIgnoreCase(fileEntry.Value, "url");
+                var hashBytes = ReadByteArrayIgnoreCase(fileEntry.Value, "archivesha512")
+                                ?? ReadByteArrayIgnoreCase(fileEntry.Value, "filesha512");
+
+                if (string.IsNullOrWhiteSpace(downloadUrl) || hashBytes is null || hashBytes.Length == 0)
+                {
+                    continue;
+                }
+
+                var hashHex = Convert.ToHexString(hashBytes).ToLowerInvariant();
+                entries.Add(new PdcDownloadEntry(
+                    component.Name,
+                    fileEntry.Name,
+                    downloadUrl,
+                    hashHex));
+            }
+        }
+
+        return entries;
+    }
+
+    private static async Task<string?> ComputeFileSha512HexAsync(string filePath, CancellationToken cancellationToken)
+    {
+        if (!File.Exists(filePath))
+        {
+            return null;
+        }
+
+        await using var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
+        var hashBytes = await SHA512.HashDataAsync(stream, cancellationToken);
+        return Convert.ToHexString(hashBytes).ToLowerInvariant();
+    }
+
+    private static bool TryGetPropertyIgnoreCase(JsonElement node, string propertyName, out JsonElement value)
+    {
+        if (node.ValueKind == JsonValueKind.Object)
+        {
+            foreach (var property in node.EnumerateObject())
+            {
+                if (string.Equals(property.Name, propertyName, StringComparison.OrdinalIgnoreCase))
+                {
+                    value = property.Value;
+                    return true;
+                }
+            }
+        }
+
+        value = default;
+        return false;
+    }
+
+    private static string? ReadStringIgnoreCase(JsonElement node, string propertyName)
+    {
+        return TryGetPropertyIgnoreCase(node, propertyName, out var value)
+            ? value.ValueKind == JsonValueKind.String
+                ? value.GetString()
+                : value.ToString()
+            : null;
+    }
+
+    private static byte[]? ReadByteArrayIgnoreCase(JsonElement node, string propertyName)
+    {
+        if (!TryGetPropertyIgnoreCase(node, propertyName, out var value))
+        {
+            return null;
+        }
+
+        return ReadByteArray(value);
+    }
+
+    private static byte[]? ReadByteArray(JsonElement value)
+    {
+        switch (value.ValueKind)
+        {
+            case JsonValueKind.String:
+            {
+                var text = value.GetString()?.Trim();
+                if (string.IsNullOrWhiteSpace(text))
+                {
+                    return null;
+                }
+
+                if (IsHexString(text))
+                {
+                    try
+                    {
+                        return Convert.FromHexString(text);
+                    }
+                    catch
+                    {
+                        // fall through to base64
+                    }
+                }
+
+                try
+                {
+                    return Convert.FromBase64String(text);
+                }
+                catch
+                {
+                    return null;
+                }
+            }
+            case JsonValueKind.Array:
+            {
+                var bytes = new List<byte>();
+                foreach (var item in value.EnumerateArray())
+                {
+                    if (!item.TryGetInt32(out var number) || number is < byte.MinValue or > byte.MaxValue)
+                    {
+                        return null;
+                    }
+
+                    bytes.Add((byte)number);
+                }
+
+                return bytes.ToArray();
+            }
+            default:
+                return null;
+        }
+    }
+
+    private static bool IsHexString(string value)
+    {
+        if (string.IsNullOrWhiteSpace(value) || value.Length % 2 != 0)
+        {
+            return false;
+        }
+
+        foreach (var ch in value)
+        {
+            if (!Uri.IsHexDigit(ch))
+            {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    private sealed record PdcDownloadEntry(
+        string ComponentId,
+        string RelativePath,
+        string DownloadUrl,
+        string ObjectHashHex);
+
+    private sealed record PdcDownloadedObjectInfo(
+        string ComponentId,
+        string RelativePath,
+        string SourceUrl,
+        string ObjectHashHex,
+        string LocalPath);
+
+    private sealed record PdcUpdateState(
+        string VersionText,
+        string DistributionId,
+        string ChannelId,
+        string SubChannel,
+        string FileMapPath,
+        string FileMapSignaturePath,
+        string ObjectsDirectory,
+        DateTimeOffset DownloadedAtUtc,
+        string FileMapJson,
+        string FileMapSignature,
+        IReadOnlyList<PdcDownloadedObjectInfo> Objects);
+
     private static bool TryResolveDeltaAssets(
         IReadOnlyList<GitHubReleaseAsset> assets,
         out GitHubReleaseAsset manifestAsset,
@@ -327,6 +776,11 @@ public sealed class UpdateWorkflowService
     {
         ArgumentNullException.ThrowIfNull(checkResult);
 
+        if (checkResult.PdcPayload is not null)
+        {
+            return await DownloadDeltaUpdateAsync(checkResult, progress, cancellationToken);
+        }
+
         if (!checkResult.Success || !checkResult.IsUpdateAvailable || checkResult.Release is null || checkResult.PreferredAsset is null)
         {
             return new UpdateDownloadResult(false, null, "No compatible update asset is available.");
@@ -365,9 +819,9 @@ public sealed class UpdateWorkflowService
             {
                 PendingUpdateInstallerPath = result.FilePath ?? destinationPath,
                 PendingUpdateVersion = checkResult.LatestVersionText,
-                PendingUpdatePublishedAtUtcMs = checkResult.Release.PublishedAt == DateTimeOffset.MinValue
+                PendingUpdatePublishedAtUtcMs = checkResult.Release?.PublishedAt is DateTimeOffset publishedAt && publishedAt != DateTimeOffset.MinValue
-                    ? null
+                    ? publishedAt.ToUnixTimeMilliseconds()
-                    : checkResult.Release.PublishedAt.ToUnixTimeMilliseconds(),
+                    : null,
                 LastUpdateCheckUtcMs = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
                 PendingUpdateSha256 = result.ActualHash
             });
@@ -383,6 +837,12 @@ public sealed class UpdateWorkflowService
     {
         ArgumentNullException.ThrowIfNull(checkResult);
 
+        if (checkResult.PdcPayload is not null)
+        {
+            ClearPendingUpdate();
+            return await DownloadDeltaUpdateAsync(checkResult, progress, cancellationToken);
+        }
+
         if (!checkResult.Success || !checkResult.IsUpdateAvailable || checkResult.Release is null || checkResult.PreferredAsset is null)
         {
             return new UpdateDownloadResult(false, null, "No compatible update asset is available.");
@@ -426,9 +886,9 @@ public sealed class UpdateWorkflowService
             {
                 PendingUpdateInstallerPath = result.FilePath ?? destinationPath,
                 PendingUpdateVersion = checkResult.LatestVersionText,
-                PendingUpdatePublishedAtUtcMs = checkResult.Release.PublishedAt == DateTimeOffset.MinValue
+                PendingUpdatePublishedAtUtcMs = checkResult.Release?.PublishedAt is DateTimeOffset publishedAt && publishedAt != DateTimeOffset.MinValue
-                    ? null
+                    ? publishedAt.ToUnixTimeMilliseconds()
-                    : checkResult.Release.PublishedAt.ToUnixTimeMilliseconds(),
+                    : null,
                 LastUpdateCheckUtcMs = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds(),
                 PendingUpdateSha256 = result.ActualHash
             });
@@ -449,9 +909,27 @@ public sealed class UpdateWorkflowService
 
         if (!File.Exists(pending.InstallerPath))
         {
+            if (IsPendingDeltaUpdate())
+            {
+                var pdcUpdatePath = pending.InstallerPath;
+                var pdcFileMapPath = Path.Combine(Path.GetDirectoryName(pdcUpdatePath) ?? string.Empty, PdcFileMapName);
+                var pdcSignaturePath = Path.Combine(Path.GetDirectoryName(pdcUpdatePath) ?? string.Empty, PdcFileMapSignatureName);
+                if (File.Exists(pdcUpdatePath) && File.Exists(pdcFileMapPath) && File.Exists(pdcSignaturePath))
+                {
+                    return new UpdateVerifyResult(true, true, null, null, null);
+                }
+
+                return new UpdateVerifyResult(false, false, null, null, "PDC update payload is incomplete.");
+            }
+
             return new UpdateVerifyResult(false, false, null, null, "Installer file does not exist.");
         }
 
+        if (IsPendingDeltaUpdate())
+        {
+            return new UpdateVerifyResult(true, true, null, null, null);
+        }
+
         var expectedHash = pending.Sha256;
         var actualHash = await GitHubReleaseUpdateService.ComputeFileSha256Async(pending.InstallerPath);
 
@@ -483,7 +961,7 @@ public sealed class UpdateWorkflowService
         {
             // Always check for updates on startup (removed AutoCheckUpdates check)
             var result = await CheckForUpdatesAsync(currentVersion, isForce: false, cancellationToken);
-            if (!result.Success || !result.IsUpdateAvailable || result.Release is null)
+            if (!result.Success || !result.IsUpdateAvailable || (result.Release is null && result.PdcPayload is null))
             {
                 return;
             }
@@ -495,7 +973,7 @@ public sealed class UpdateWorkflowService
                 string.Equals(normalizedMode, UpdateSettingsValues.ModeSilentOnExit, StringComparison.OrdinalIgnoreCase))
             {
                 // Prefer delta update if available (smaller download, faster)
-                if (IsDeltaUpdateAvailable(result.Release))
+                if (IsDeltaUpdateAvailable(result))
                 {
                     AppLogger.Info("UpdateWorkflow", "Delta update available, downloading incremental package.");
                     await DownloadDeltaUpdateAsync(result, cancellationToken: cancellationToken);
@@ -519,6 +997,14 @@ public sealed class UpdateWorkflowService
 
     public UpdateInstallerLaunchResult LaunchPendingInstallerNow()
     {
+        if (IsPendingDeltaUpdate())
+        {
+            var launchResult = LaunchLauncherForApplyUpdate();
+            return launchResult
+                ? new UpdateInstallerLaunchResult(true, false, null)
+                : new UpdateInstallerLaunchResult(false, false, "Failed to launch updater for incremental update.");
+        }
+
         return LaunchPendingInstaller(silent: false, exitApplicationAfterLaunch: true);
     }
 

phainon.yml

@@ -1,7 +1,5 @@
-# Phainon Distribution Center (PDC) publish configuration
+# Phainon Distribution Center Client Configuration
-# This file is intentionally conservative: Launcher remains installer/rollback authority.
 name: "LanMountainDesktop"
-
 components:
   app:
     allowDiffUpdate: true
@@ -13,17 +11,13 @@ components:
     includes:
       - "**"
     excludes:
-      - "app-*/**"
+      - "app*/**"
-      - ".launcher/update/incoming/**"
+      - "files*.json"
-      - "files.json"
+      - "files*.json.sig"
-      - "files.json.sig"
+      - "update*.zip"
-      - "update.zip"
-
 variables:
   number: 0
-
+fileRepoRoot: "__FILE_REPO_ROOT__"
-# Replace these roots in CI/CD or environment-specific templates when enabling PDCC publish.
+archiveRoot: "__ARCHIVE_ROOT__"
-fileRepoRoot: "https://example.invalid/lanmountain/distribution-v1/repo/"
+bucketKeyRoot: "lanmountain/update/repo/"
-archiveRoot: "https://example.invalid/lanmountain/distribution-v1/$(primaryVersion)/$(version)/"
+archiveBucketKeyRoot: "lanmountain/update/installers/"
-bucketKeyRoot: "lanmountain/distribution-v1/repo/"
-archiveBucketKeyRoot: "lanmountain/distribution-v1/$(primaryVersion)/$(version)/"

scripts/Install-Pdcc.ps1

@@ -0,0 +1,101 @@
+param(
+    [string]$Repository = "ClassIsland/PhainonDistributionCenter",
+    [string]$AssetName = "out_app_linux_x64.zip",
+    [string]$Version = "",
+    [string]$OutputDir = (Join-Path $PSScriptRoot "..\pdcc")
+)
+
+$ErrorActionPreference = "Stop"
+
+if ([string]::IsNullOrWhiteSpace($Repository)) {
+    throw "Repository is required."
+}
+
+if ([string]::IsNullOrWhiteSpace($AssetName)) {
+    throw "AssetName is required."
+}
+
+$OutputDir = [System.IO.Path]::GetFullPath($OutputDir)
+if (-not (Test-Path -LiteralPath $OutputDir)) {
+    New-Item -ItemType Directory -Path $OutputDir -Force | Out-Null
+}
+
+$clientName = if ($env:OS -eq "Windows_NT") { "PhainonDistributionCenter.Client.exe" } else { "PhainonDistributionCenter.Client" }
+$clientPath = Join-Path $OutputDir $clientName
+if (Test-Path -LiteralPath $clientPath) {
+    Write-Host "PDCC client already installed at $clientPath"
+    return
+}
+
+$releaseTag = $Version
+if ([string]::IsNullOrWhiteSpace($releaseTag)) {
+    $releaseTag = $env:PDC_CLIENT_VERSION
+}
+
+if ([string]::IsNullOrWhiteSpace($releaseTag)) {
+    $releaseTag = $env:PDCC_VERSION
+}
+
+if ([string]::IsNullOrWhiteSpace($releaseTag)) {
+    $releaseTag = $env:PDCC_version
+}
+
+$tempDir = Join-Path $env:RUNNER_TEMP "pdcc-install"
+if (Test-Path -LiteralPath $tempDir) {
+    Remove-Item -LiteralPath $tempDir -Recurse -Force
+}
+New-Item -ItemType Directory -Path $tempDir -Force | Out-Null
+
+$zipPath = Join-Path $tempDir $AssetName
+
+if (Get-Command gh -ErrorAction SilentlyContinue) {
+    Write-Host "Downloading PDCC via gh release download from $Repository ..."
+    $ghArgs = @("release", "download", "--repo", $Repository, "--pattern", $AssetName, "--dir", $tempDir, "--clobber")
+    if (-not [string]::IsNullOrWhiteSpace($releaseTag)) {
+        $ghArgs = @("release", "download", $releaseTag, "--repo", $Repository, "--pattern", $AssetName, "--dir", $tempDir, "--clobber")
+    }
+
+    & gh @ghArgs
+    if ($LASTEXITCODE -ne 0) {
+        throw "gh release download failed for $Repository/$AssetName."
+    }
+}
+else {
+    if ([string]::IsNullOrWhiteSpace($releaseTag)) {
+        throw "PDCC_VERSION is required when gh is unavailable."
+    }
+
+    $downloadUrl = "https://github.com/$Repository/releases/download/$releaseTag/$AssetName"
+    Write-Host "Downloading PDCC from $downloadUrl ..."
+    Invoke-WebRequest -Uri $downloadUrl -OutFile $zipPath
+}
+
+$extractDir = Join-Path $tempDir "extract"
+if (Test-Path -LiteralPath $extractDir) {
+    Remove-Item -LiteralPath $extractDir -Recurse -Force
+}
+New-Item -ItemType Directory -Path $extractDir -Force | Out-Null
+Expand-Archive -LiteralPath $zipPath -DestinationPath $extractDir -Force
+
+$copied = $false
+foreach ($file in Get-ChildItem -LiteralPath $extractDir -Recurse -File) {
+    if ($file.Name -ieq $clientName) {
+        Copy-Item -LiteralPath $file.FullName -Destination $clientPath -Force
+        $copied = $true
+        break
+    }
+}
+
+if (-not $copied) {
+    throw "PDCC client executable not found in downloaded archive."
+}
+
+if ($IsLinux) {
+    try {
+        chmod +x $clientPath | Out-Null
+    }
+    catch {
+    }
+}
+
+Write-Host "PDCC installed to $clientPath"

scripts/Prepare-PdccOut.ps1

@@ -0,0 +1,59 @@
+param(
+    [Parameter(Mandatory = $true)]
+    [string]$SourceDir,
+
+    [Parameter(Mandatory = $true)]
+    [string]$OutputDir,
+
+    [string]$PlatformKey = "",
+
+    [string[]]$InstallerFiles = @()
+)
+
+$ErrorActionPreference = "Stop"
+
+$SourceDir = [System.IO.Path]::GetFullPath($SourceDir)
+$OutputDir = [System.IO.Path]::GetFullPath($OutputDir)
+
+if (-not (Test-Path -LiteralPath $SourceDir)) {
+    throw "Source directory not found: $SourceDir"
+}
+
+if (Test-Path -LiteralPath $OutputDir) {
+    Remove-Item -LiteralPath $OutputDir -Recurse -Force
+}
+New-Item -ItemType Directory -Path $OutputDir -Force | Out-Null
+
+$payloadRoot = if ([string]::IsNullOrWhiteSpace($PlatformKey)) {
+    $OutputDir
+} else {
+    Join-Path $OutputDir $PlatformKey
+}
+
+New-Item -ItemType Directory -Path $payloadRoot -Force | Out-Null
+Get-ChildItem -LiteralPath $SourceDir -Force | ForEach-Object {
+    Copy-Item -LiteralPath $_.FullName -Destination $payloadRoot -Recurse -Force
+}
+
+if ($InstallerFiles.Count -gt 0) {
+    $installerRoot = Join-Path $OutputDir "installers"
+    if (-not (Test-Path -LiteralPath $installerRoot)) {
+        New-Item -ItemType Directory -Path $installerRoot -Force | Out-Null
+    }
+
+    foreach ($installer in $InstallerFiles) {
+        if ([string]::IsNullOrWhiteSpace($installer)) {
+            continue
+        }
+
+        $installerPath = [System.IO.Path]::GetFullPath($installer)
+        if (-not (Test-Path -LiteralPath $installerPath)) {
+            throw "Installer file not found: $installerPath"
+        }
+
+        $targetPath = Join-Path $installerRoot ([System.IO.Path]::GetFileName($installerPath))
+        Copy-Item -LiteralPath $installerPath -Destination $targetPath -Force
+    }
+}
+
+Write-Host "Prepared PDCC staging directory: $payloadRoot"