Refactor DataLocationResolver to centralize data path resolution (ResolveLauncherDataPath, ResolveDesktopDataPath, ResolveConfigPath, ResolveLauncherLogsPath, ResolveLauncherStatePath) and replace usages of the previous ".launcher" layout with a "Launcher" folder. Update API: LoadConfig/SaveConfig reorganized and ApplyLocationChoice now accepts an optional custom path and migration flag; migration logic updated accordingly. Update dependent services and views (Logger, DeploymentLocator, UpdateEngineService, OobeStateService, StartupAttemptRegistry, LauncherDebugSettingsStore, OobeWindow) to use the new resolver APIs and paths. Add LauncherBackgroundService to load/validate/cache a custom splash background image and wire it into SplashWindow (AXAML/Axaml.cs) with UI placeholders and overlay. Misc: minor cleanup of Oobe/Splash XAML and related code adjustments and logging improvements.
Introduce support for choosing and resolving the application's data root (system user dir vs. portable app folder). Adds DataLocationConfig model, DataLocationResolver (load/save/resolve/migrate), a UI prompt (DataLocationPromptWindow) and an OOBE step (DataLocationOobeStep) to let users pick and optionally migrate existing data. Wire the chosen data root into the launcher flow and host launch plan (forwarded via --data-root and LMD_DATA_ROOT), and add AppDataPathProvider to let runtime services read the effective data root (initialized in Program.Main). Update various services (logging, settings, DB, plugin/market, startup registry, etc.) to use the new provider/resolver and register the config type in the JSON context. This enables portable installs, safe migration, and runtime overrides via CLI or environment variable.
Introduce a persistent LauncherDebugSettingsStore and wire it into ErrorWindow and SplashWindow so dev-mode and custom host path can be saved/loaded. Harden DeploymentLocator/FlexibleHostLocator to safely normalize and validate saved debug paths and log warnings for malformed values. Add a WaitingForShell startup state and recoverable-activation logic across App and LauncherFlowCoordinator (with registry updates) so Launcher can attach to an in-progress desktop shell rather than failing. Clean up ErrorDebugWindow UI/flow (WasAccepted flag, localization fixes, event wiring) and improve splash version population. Improve AppVersionProvider to trim surrounding quotes, robustly parse version.json via JsonDocument and read string properties; add unit tests for AppVersionProvider, DeploymentLocator and LauncherDebugSettingsStore. Also quote Exec commands in the csproj and harden scripts/Generate-VersionFile.ps1 (argument normalization, LiteralPath, error handling).
