feat(launcher): Campaign LA add Avalonia desktop shell

src/AcDream.Launcher.Core/Launching/LauncherProcessSupervisor.cs

@@ -2,13 +2,47 @@ using System.Runtime.ExceptionServices;
 
 namespace AcDream.Launcher.Core.Launching;
 
+/// <summary>
+/// Test seam for one supervised launcher child. The Avalonia orchestration
+/// layer owns this interface through a factory and never constructs or drives
+/// <see cref="System.Diagnostics.Process"/> directly.
+/// </summary>
+public interface ILauncherProcessSupervisor : IDisposable
+{
+    LauncherSessionState State { get; }
+
+    int? ExitCode { get; }
+
+    event EventHandler<LauncherSessionState>? StateChanged;
+
+    void Start(LauncherProcessSpec spec, string? password);
+
+    void Stop(TimeSpan timeout);
+}
+
+public interface ILauncherProcessSupervisorFactory
+{
+    ILauncherProcessSupervisor Create();
+}
+
+public sealed class LauncherProcessSupervisorFactory(
+    ILauncherChildProcessFactory? childProcessFactory = null)
+    : ILauncherProcessSupervisorFactory
+{
+    private readonly ILauncherChildProcessFactory _childProcessFactory =
+        childProcessFactory ?? new SystemChildProcessFactory();
+
+    public ILauncherProcessSupervisor Create() =>
+        new LauncherProcessSupervisor(_childProcessFactory);
+}
+
 /// <summary>
 /// Spawns a host process (App/Headless), feeds the account password to
 /// its stdin then closes it, and supervises its lifetime (Campaign LA
 /// spec §3/§6). One supervisor instance owns exactly one child process
 /// for its lifetime — start a new supervisor per launched session.
 /// </summary>
-public sealed class LauncherProcessSupervisor : IDisposable
+public sealed class LauncherProcessSupervisor : ILauncherProcessSupervisor
 {
     private readonly ILauncherChildProcessFactory _factory;
     private readonly object _gate = new();

src/AcDream.Launcher.Core/Launching/SessionConfigComposer.cs

@@ -13,6 +13,64 @@ public sealed record ComposedSessionConfig(
     string StatusFilePath,
     SessionConfigDocument Document);
 
+/// <summary>
+/// Injectable composition/write seam used by the canonical launcher
+/// orchestrator. Production delegates to <see cref="SessionConfigComposer"/>;
+/// tests can capture the exact request without writing a file or starting a
+/// client process.
+/// </summary>
+public interface ILauncherSessionConfigService
+{
+    ComposedSessionConfig ComposeAndWrite(
+        ServerProfile server,
+        AccountProfile account,
+        CharacterProfile character,
+        LauncherInstallRecord install,
+        ApplicationPathSet paths,
+        string sessionId,
+        int? loginCommandDelayMs = null);
+
+    ComposedSessionConfig ComposeProbeAndWrite(
+        ServerProfile server,
+        AccountProfile account,
+        LauncherInstallRecord install,
+        ApplicationPathSet paths,
+        string sessionId);
+}
+
+public sealed class LauncherSessionConfigService : ILauncherSessionConfigService
+{
+    public ComposedSessionConfig ComposeAndWrite(
+        ServerProfile server,
+        AccountProfile account,
+        CharacterProfile character,
+        LauncherInstallRecord install,
+        ApplicationPathSet paths,
+        string sessionId,
+        int? loginCommandDelayMs = null) =>
+        SessionConfigComposer.ComposeAndWrite(
+            server,
+            account,
+            character,
+            install,
+            paths,
+            sessionId,
+            loginCommandDelayMs);
+
+    public ComposedSessionConfig ComposeProbeAndWrite(
+        ServerProfile server,
+        AccountProfile account,
+        LauncherInstallRecord install,
+        ApplicationPathSet paths,
+        string sessionId) =>
+        SessionConfigComposer.ComposeProbeAndWrite(
+            server,
+            account,
+            install,
+            paths,
+            sessionId);
+}
+
 /// <summary>
 /// Builds the per-launch <see cref="SessionConfigDocument"/> from a
 /// profile character + install record (Campaign LA spec §6). Passwords
@@ -187,6 +245,23 @@ public static class SessionConfigComposer
             sessionId,
             loginCommandDelayMs);
 
+        return Write(composed);
+    }
+
+    /// <summary>Probe counterpart to <see cref="ComposeAndWrite"/>. It
+    /// writes the pinned <c>mode: "probe"</c> document and never includes
+    /// a character selector, policy, plugin set, login commands, or password.
+    /// </summary>
+    public static ComposedSessionConfig ComposeProbeAndWrite(
+        ServerProfile server,
+        AccountProfile account,
+        LauncherInstallRecord install,
+        ApplicationPathSet paths,
+        string sessionId) =>
+        Write(ComposeProbe(server, account, install, paths, sessionId));
+
+    private static ComposedSessionConfig Write(ComposedSessionConfig composed)
+    {
         string? directory = Path.GetDirectoryName(composed.ConfigFilePath);
         if (!string.IsNullOrEmpty(directory))
         {