task_queue 三处 connect 补 Qt.QueuedConnection (等价 master a8d0cf0f)

master 上 a8d0cf0f 修过：worker_ref.{finished,error,progress}.connect
默认 DirectConnection，lambda 在 worker 线程同步执行，链路尽头动主线程
GUI (refresh_history / sidebar 刷新) → C++ access violation。
Windows 表现为 fatal exception，macOS 表现为静默 SIGKILL 闪退。

qml-poc 从 5f2a43f7 fork，没拿到这个修复。直接合回 master 会带着雷。
不 cherry-pick 原因：qml-poc 已把 'from image_generator import' 改成
'from core.generation import'，cherry-pick a8d0cf0f 会冲突。
手工等价应用更干净。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

@@ -209,17 +209,24 @@ class TaskQueueManager(QObject):
 
 
         # 绑定信号；用 worker 局部引用捕获 finish_reason，避免后续 _current_worker 被替换
         # 绑定信号；用 worker 局部引用捕获 finish_reason，避免后续 _current_worker 被替换
         worker_ref = self._current_worker
         worker_ref = self._current_worker
+        # 🔒 必须 QueuedConnection: worker_ref 是 QThread, finished/error/progress 从 worker 线程发出。
+        # lambda 没有 QObject thread affinity, 默认会被当成 DirectConnection 在 worker 线程同步执行,
+        # 链路尽头会动主线程 GUI (refresh_history / sidebar 刷新), C++ 层 access violation。
+        # Windows 表现为 fatal exception, macOS 表现为静默 SIGKILL 闪退。
         worker_ref.finished.connect(
         worker_ref.finished.connect(
             lambda img_bytes, prompt, ref_imgs, ar, size, model:
             lambda img_bytes, prompt, ref_imgs, ar, size, model:
                 self._on_task_completed(task_id, img_bytes, prompt, ref_imgs, ar, size, model,
                 self._on_task_completed(task_id, img_bytes, prompt, ref_imgs, ar, size, model,
-                                        getattr(worker_ref, 'finish_reason', None))
+                                        getattr(worker_ref, 'finish_reason', None)),
+            Qt.QueuedConnection,
         )
         )
         worker_ref.error.connect(
         worker_ref.error.connect(
             lambda error: self._on_task_failed(task_id, error,
             lambda error: self._on_task_failed(task_id, error,
-                                               getattr(worker_ref, 'finish_reason', None))
+                                               getattr(worker_ref, 'finish_reason', None)),
+            Qt.QueuedConnection,
         )
         )
         worker_ref.progress.connect(
         worker_ref.progress.connect(
-            lambda status: self.task_progress.emit(task_id, 0.5, status)
+            lambda status: self.task_progress.emit(task_id, 0.5, status),
+            Qt.QueuedConnection,
         )
         )
 
 
         self.task_started.emit(task_id)
         self.task_started.emit(task_id)