feat(startup): 支持等待 ContextLoader 启动

Runtime/ShrinkAppLoaderBootstrapper.cs

@@ -1,6 +1,9 @@
 #nullable enable
+using System;
+using System.Threading;
 using Cysharp.Threading.Tasks;
 using ShrinkApp;
+using ShrinkEventBus;
 using UnityEngine;
 
 namespace ShrinkContext.AppAdapter
@@ -14,6 +17,7 @@ namespace ShrinkContext.AppAdapter
     public sealed class ShrinkAppLoaderBootstrapper : MonoBehaviour
     {
         private static ShrinkAppLoaderBootstrapper? _instance;
+        private static UniTaskCompletionSource _startupCompletion = new();
 
         /// <summary>
         /// Starter/组合包在 SubsystemRegistration 阶段设置的默认装配表。
@@ -22,9 +26,43 @@ namespace ShrinkContext.AppAdapter
         public static System.Action<ShrinkAppLoaderHost>? DefaultComposition { get; set; }
 
         public static ShrinkAppLoaderBootstrapper? Instance => _instance;
+        public static Exception? StartError { get; private set; }
 
         public ShrinkAppLoaderHost Host { get; private set; } = null!;
 
+        /// <summary>
+        /// 等待 ContextLoader 宿主完成启动。支持多个并发等待者；宿主失败时以原始异常结束。
+        /// </summary>
+        public static async UniTask WaitUntilStartedAsync(CancellationToken cancellationToken = default)
+        {
+            if (_instance?.Host?.IsRunning == true)
+                return;
+            if (StartError != null)
+                throw StartError;
+            if (ShrinkAppSettings.Instance.hostingMode != ShrinkAppHostingMode.ContextLoader)
+            {
+                throw new InvalidOperationException(
+                    "ShrinkAppLoaderBootstrapper requires ShrinkAppHostingMode.ContextLoader.");
+            }
+
+            var task = _startupCompletion.Task;
+            if (cancellationToken.CanBeCanceled)
+                await task.AttachExternalCancellation(cancellationToken);
+            else
+                await task;
+
+            if (StartError != null)
+                throw StartError;
+        }
+
+        [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
+        private static void ResetStaticState()
+        {
+            _instance = null;
+            StartError = null;
+            _startupCompletion = new UniTaskCompletionSource();
+        }
+
         [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
         private static void AutoBootstrap()
         {
@@ -45,17 +83,39 @@ namespace ShrinkContext.AppAdapter
             }
 
             _instance = this;
-            Host = new ShrinkAppLoaderHost();
-            DefaultComposition?.Invoke(Host);
-            var profile = ShrinkAppCompositionProfile.LoadDefault();
-            if (profile != null)
-                Host.ApplyComposition(profile.ResolveDocument());
-            global::ShrinkApp.ShrinkApp.InitializeForExternalHost(Host.Services);
-            Host.StartAsync().Forget(ex =>
+            StartHostAsync().Forget();
+        }
+
+        private async UniTask StartHostAsync()
+        {
+            try
             {
+                Host = new ShrinkAppLoaderHost();
+                DefaultComposition?.Invoke(Host);
+                var profile = ShrinkAppCompositionProfile.LoadDefault();
+                if (profile != null)
+                    Host.ApplyComposition(profile.ResolveDocument());
+                global::ShrinkApp.ShrinkApp.InitializeForExternalHost(Host.Services);
+                await Host.StartAsync();
+                CompleteStartup(null);
+            }
+            catch (Exception ex)
+            {
+                CompleteStartup(ex);
+                EventBus.Post(new ShrinkAppStartFailedEvent
+                {
+                    ErrorMessage = ex.Message,
+                    FailedModuleId = string.Empty
+                });
                 Debug.LogException(ex);
                 Debug.LogError("[ShrinkApp.LoaderHost] 启动失败: " + ex.Message);
-            });
+            }
+        }
+
+        private static void CompleteStartup(Exception? error)
+        {
+            StartError = error;
+            _startupCompletion.TrySetResult();
         }
 
         private void OnDestroy()