fix.修ci，修融合桌面，修启动器

LanMountainDesktop.Shared.Contracts/Launcher/HostExitCodes.cs

@@ -0,0 +1,18 @@
+namespace LanMountainDesktop.Shared.Contracts.Launcher;
+
+/// <summary>
+/// Standardized host process exit codes consumed by the launcher.
+/// </summary>
+public static class HostExitCodes
+{
+    public const int Success = 0;
+
+    // Secondary instance activated the existing primary instance successfully.
+    public const int SecondaryActivationSucceeded = 12;
+
+    // Secondary instance failed to activate the existing primary instance.
+    public const int SecondaryActivationFailed = 13;
+
+    // Restart relaunch couldn't acquire the single-instance lock in time.
+    public const int RestartLockNotAcquired = 14;
+}