Add startup visual modes and attempt registry

Implement startup visual behavior, de-duplicate startup attempts, and improve failure UX.

Key changes:
- Add spec and docs for startup visuals and timing contract (.trae/specs and docs/LAUNCHER_STARTUP_VISUALS.md).
- Introduce StartupVisualPreferences contract and resolver; create SplashWindow via resolved mode.
- Add StartupAttemptRecord model and a file-backed StartupAttemptRegistry to persist and coordinate in-progress startup attempts (attach/adopt, soft/hard timeouts, IPC/connect state, lifecycle updates).
- Update LauncherFlowCoordinator to: adopt/attach to existing attempts, track IPC connection and soft/hard timeouts (30s/120s), show delayed UI state, attempt foreground recovery via public IPC, compose detailed launch result metadata, and mark registry states (soft timeout, detached waiting, succeeded, failed).
- Add TryActivateExistingInstanceAsync to attempt activating an existing desktop via IPC.
- Change failure flow: ShowFailureWindowAsync now returns user choice; ErrorWindow updated to present Activate/Wait/Open Logs/Exit semantics and new layouts/styles; improved button wiring and debug/dev mode handling.
- Add UI and resource tweaks (ErrorWindow and SplashWindow changes), project asset link for nightly logo, and unit tests for StartupVisualPreferences.

These changes prevent duplicate desktop processes during slow startups, provide clearer UX for delayed startups, and persist startup attempt state across Launcher invocations for safer recovery/attach behavior.

LanMountainDesktop.Launcher/App.axaml.cs

@@ -6,6 +6,9 @@ using Avalonia.Threading;
 using LanMountainDesktop.Launcher.Models;
 using LanMountainDesktop.Launcher.Services;
 using LanMountainDesktop.Launcher.Views;
+using LanMountainDesktop.Shared.Contracts.Launcher;
+using LanMountainDesktop.Shared.IPC;
+using LanMountainDesktop.Shared.IPC.Abstractions.Services;
 
 namespace LanMountainDesktop.Launcher;
 
@@ -52,7 +55,7 @@ public partial class App : Application
             }
             else
             {
-                var splashWindow = new SplashWindow();
+                var splashWindow = CreateSplashWindow();
                 splashWindow.Show();
                 _ = RunCoordinatorWithSplashAsync(desktop, context, splashWindow);
             }
@@ -68,7 +71,7 @@ public partial class App : Application
             case "preview-splash":
             {
                 Logger.Info("Preview command: splash.");
-                var splashWindow = new SplashWindow();
+                var splashWindow = CreateSplashWindow();
                 splashWindow.SetDebugMode(true);
                 splashWindow.Show();
                 _ = SimulateSplashPreviewAsync(desktop, splashWindow);
@@ -112,6 +115,12 @@ public partial class App : Application
         }
     }
 
+    private static SplashWindow CreateSplashWindow()
+    {
+        var preferences = StartupVisualPreferencesResolver.Resolve();
+        return new SplashWindow(preferences.Mode);
+    }
+
     private async Task SimulateSplashPreviewAsync(IClassicDesktopStyleApplicationLifetime desktop, SplashWindow window)
     {
         var stages = new[] { "initializing", "update", "plugins", "launch", "ready" };
@@ -172,49 +181,76 @@ public partial class App : Application
         SplashWindow splashWindow)
     {
         LauncherResult result;
+        SplashWindow? currentSplashWindow = splashWindow;
+        var appRoot = Commands.ResolveAppRoot(context);
 
-        try
+        while (true)
         {
-            var appRoot = Commands.ResolveAppRoot(context);
-            Logger.Info(
-                $"Coordinator start. Command='{context.Command}'; AppRoot='{appRoot}'; " +
-                $"IsDebugMode={context.IsDebugMode}; LaunchSource='{context.LaunchSource}'; " +
-                $"ResultPath='{context.GetOption("result") ?? "<none>"}'.");
-
-            var deploymentLocator = new DeploymentLocator(appRoot);
-            var coordinator = new LauncherFlowCoordinator(
-                context,
-                deploymentLocator,
-                new OobeStateService(appRoot),
-                new UpdateEngineService(deploymentLocator),
-                new PluginInstallerService());
-
-            result = await coordinator.RunAsync(splashWindow).ConfigureAwait(false);
-        }
-        catch (Exception ex)
-        {
-            Logger.Error("Coordinator threw an unhandled exception.", ex);
-            result = new LauncherResult
+            try
             {
-                Success = false,
-                Stage = "launch",
-                Code = "exception",
-                Message = $"Launcher failed: {ex.Message}",
-                ErrorMessage = ex.ToString()
-            };
+                Logger.Info(
+                    $"Coordinator start. Command='{context.Command}'; AppRoot='{appRoot}'; " +
+                    $"IsDebugMode={context.IsDebugMode}; LaunchSource='{context.LaunchSource}'; " +
+                    $"ResultPath='{context.GetOption("result") ?? "<none>"}'.");
+
+                var deploymentLocator = new DeploymentLocator(appRoot);
+                var coordinator = new LauncherFlowCoordinator(
+                    context,
+                    deploymentLocator,
+                    new OobeStateService(appRoot),
+                    new UpdateEngineService(deploymentLocator),
+                    new PluginInstallerService());
+
+                result = await coordinator.RunAsync(currentSplashWindow).ConfigureAwait(false);
+            }
+            catch (Exception ex)
+            {
+                Logger.Error("Coordinator threw an unhandled exception.", ex);
+                result = new LauncherResult
+                {
+                    Success = false,
+                    Stage = "launch",
+                    Code = "exception",
+                    Message = $"Launcher failed: {ex.Message}",
+                    ErrorMessage = ex.ToString()
+                };
+            }
+
+            if (result.Success ||
+                result.Code == "host_not_found" ||
+                (!string.Equals(result.Stage, "launch", StringComparison.OrdinalIgnoreCase) &&
+                 !string.Equals(result.Stage, "launchHost", StringComparison.OrdinalIgnoreCase)))
+            {
+                break;
+            }
+
+            var failureAction = await ShowFailureWindowAsync(result).ConfigureAwait(false);
+            if (failureAction == ErrorWindowResult.Exit)
+            {
+                break;
+            }
+
+            if (failureAction == ErrorWindowResult.ActivateExisting &&
+                await TryActivateExistingInstanceAsync().ConfigureAwait(false))
+            {
+                result = new LauncherResult
+                {
+                    Success = true,
+                    Stage = "launch",
+                    Code = "activation_requested",
+                    Message = "Launcher activated the existing desktop instance.",
+                    Details = result.Details
+                };
+                break;
+            }
+
+            currentSplashWindow = CreateSplashWindow();
+            currentSplashWindow.Show();
         }
 
         Logger.Info($"Coordinator completed. Success={result.Success}; Stage='{result.Stage}'; Code='{result.Code}'.");
         await WriteLauncherResultAsync(context, result).ConfigureAwait(false);
 
-        if (!result.Success &&
-            result.Code is not "host_not_found" &&
-            (string.Equals(result.Stage, "launch", StringComparison.OrdinalIgnoreCase) ||
-             string.Equals(result.Stage, "launchHost", StringComparison.OrdinalIgnoreCase)))
-        {
-            await ShowFailureWindowAsync(result).ConfigureAwait(false);
-        }
-
         Environment.ExitCode = result.Success ? 0 : 1;
         await Dispatcher.UIThread.InvokeAsync(() => desktop.Shutdown(Environment.ExitCode), DispatcherPriority.Background);
     }
@@ -238,15 +274,31 @@ public partial class App : Application
         }
     }
 
-    private static async Task ShowFailureWindowAsync(LauncherResult result)
+    private static async Task<ErrorWindowResult> ShowFailureWindowAsync(LauncherResult result)
     {
         ErrorWindow? errorWindow = null;
+        var hostProcessAlive = result.Details.TryGetValue("hostProcessAlive", out var hostProcessAliveText) &&
+                               bool.TryParse(hostProcessAliveText, out var hostProcessAliveValue) &&
+                               hostProcessAliveValue;
+        var hostPid = result.Details.TryGetValue("hostPid", out var hostPidText) &&
+                      int.TryParse(hostPidText, out var parsedPid)
+            ? parsedPid
+            : (int?)null;
 
         await Dispatcher.UIThread.InvokeAsync(() =>
         {
             try
             {
                 errorWindow = new ErrorWindow();
+                if (hostProcessAlive)
+                {
+                    errorWindow.ConfigureForRunningHostFailure(hostPid);
+                }
+                else
+                {
+                    errorWindow.ConfigureForGenericFailure(allowRetry: true);
+                }
+
                 errorWindow.SetErrorMessage(
                     $"Failed to start LanMountainDesktop.\n\nStage: {result.Stage}\nCode: {result.Code}\n\n{result.Message}");
                 errorWindow.Show();
@@ -259,16 +311,38 @@ public partial class App : Application
 
         if (errorWindow is null)
         {
-            return;
+            return ErrorWindowResult.Exit;
         }
 
         try
         {
-            await errorWindow.WaitForChoiceAsync().ConfigureAwait(false);
+            return await errorWindow.WaitForChoiceAsync().ConfigureAwait(false);
         }
         catch (Exception ex)
         {
             Logger.Error("Failure window closed unexpectedly.", ex);
+            return ErrorWindowResult.Exit;
+        }
+    }
+
+    private static async Task<bool> TryActivateExistingInstanceAsync()
+    {
+        try
+        {
+            using var ipcClient = new LanMountainDesktopIpcClient();
+            await ipcClient.ConnectAsync().ConfigureAwait(false);
+            if (!ipcClient.IsConnected)
+            {
+                return false;
+            }
+
+            var shellProxy = ipcClient.CreateProxy<IPublicShellControlService>();
+            return await shellProxy.ActivateMainWindowAsync().ConfigureAwait(false);
+        }
+        catch (Exception ex)
+        {
+            Logger.Warn($"Failed to activate the existing desktop instance: {ex.Message}");
+            return false;
         }
     }