feat(qml): task #14c 提示词收藏 + 删除（持久化到 config.json）

config_util.py 加 save_config(path, config) → bool
  原子写：tmp 文件 + replace，失败记日志返回 False（不抛异常）

ImageGenBridge:
  - 构造函数加 saved_prompts / config_path 参数
  - Property savedPrompts: list[str]
  - Slot addSavedPrompt(prompt): 去重 + 插入头部 + 持久化 + 信号
  - Slot removeSavedPrompt(prompt): 移除 + 持久化 + 信号
  - _persist_saved_prompts: load_config_safe → 改 saved_prompts → save_config

main_qml.py: 装 saved_prompts + config_path 给 ImageGenBridge

ImageGenTab.qml:
  - " 收藏" enabled by promptArea.text.trim().length > 0，onClicked add
  - "删除" enabled by savedPrompts.length > 0，删除当前 ComboBox 选中项
  - 快速选择 ComboBox model: imageGen.savedPrompts (响应 savedPromptsChanged 自动刷)
  - onActivated 仅在 currentText 非空时填到 promptArea

视觉验证：QML_AUTO_LOGIN=1 启动主窗口，ComboBox 已显示从 config.json 读到的
"主石换成闪耀的祖母绿"，收藏按钮在 prompt 空时正确灰。

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

@@ -21,6 +21,7 @@ from core.generation import MODEL_BY_MODE, MODEL_PRO
 class ImageGenBridge(QObject):
     apiKeyChanged = Signal()
     busyChanged = Signal()
+    savedPromptsChanged = Signal()
 
     taskSubmitted = Signal(str)                    # task_id
     taskCompleted = Signal(str, str, str, str)     # task_id, result_path, prompt, model
@@ -28,13 +29,16 @@ class ImageGenBridge(QObject):
     taskProgress = Signal(str, float, str)         # task_id, progress, status_text
 
     def __init__(self, task_queue_manager, history_manager, auth_bridge,
-                 api_key: str = "", parent=None):
+                 api_key: str = "", saved_prompts=None, config_path=None,
+                 parent=None):
         super().__init__(parent)
         self._logger = logging.getLogger(__name__)
         self._tqm = task_queue_manager
         self._history = history_manager
         self._auth = auth_bridge
         self._api_key = api_key
+        self._saved_prompts = list(saved_prompts or [])
+        self._config_path = config_path  # Path 或 None；None 时 add/remove 不持久化
 
         # 转发 TaskQueueManager 信号 → 桥层 QML 友好信号
         self._tqm.task_added.connect(self._on_task_added)
@@ -52,6 +56,10 @@ class ImageGenBridge(QObject):
     def busy(self) -> bool:
         return self._tqm.get_running_count() > 0
 
+    @Property("QVariantList", notify=savedPromptsChanged)
+    def savedPrompts(self) -> list:
+        return list(self._saved_prompts)
+
     # ---- Slots ----------------------------------------------------------
 
     @Slot(str)
@@ -60,6 +68,33 @@ class ImageGenBridge(QObject):
             self._api_key = key
             self.apiKeyChanged.emit()
 
+    @Slot(str)
+    def addSavedPrompt(self, prompt: str) -> None:
+        prompt = (prompt or "").strip()
+        if not prompt or prompt in self._saved_prompts:
+            return
+        self._saved_prompts.insert(0, prompt)
+        self._persist_saved_prompts()
+        self.savedPromptsChanged.emit()
+
+    @Slot(str)
+    def removeSavedPrompt(self, prompt: str) -> None:
+        if prompt not in self._saved_prompts:
+            return
+        self._saved_prompts.remove(prompt)
+        self._persist_saved_prompts()
+        self.savedPromptsChanged.emit()
+
+    def _persist_saved_prompts(self) -> None:
+        """更新 config.json 的 saved_prompts 字段（保留其他字段）。"""
+        if self._config_path is None:
+            return
+        from config_util import load_config_safe, save_config
+        cfg, _ = load_config_safe(self._config_path)
+        cfg["saved_prompts"] = list(self._saved_prompts)
+        if not save_config(self._config_path, cfg):
+            self._logger.warning(f"saved_prompts 持久化失败: {self._config_path}")
+
     @Slot(str, list, str, str, str, result=str)
     def submitTask(self, prompt: str, reference_images: list,
                    aspect_ratio: str, image_size: str, mode: str) -> str:

@@ -198,3 +198,20 @@ def _backup(src: Path, reason: str) -> None:
         shutil.copy2(src, dst)
     except Exception:
         pass
+
+
+def save_config(config_path: Path, config: dict) -> bool:
+    """原子写回 config.json。失败记日志，返回 False（不抛异常）。"""
+    config_path = Path(config_path)
+    try:
+        config_path.parent.mkdir(parents=True, exist_ok=True)
+        tmp = config_path.with_suffix(config_path.suffix + ".tmp")
+        tmp.write_text(
+            json.dumps(config, ensure_ascii=False, indent=2),
+            encoding="utf-8",
+        )
+        tmp.replace(config_path)
+        return True
+    except Exception as e:
+        logger.error(f"save_config 失败 {config_path}: {e}")
+        return False

@@ -103,6 +103,7 @@ def main():
 
     api_key = config.get("api_key", "") or ""
     db_config = config.get("db_config")  # None 时桥层走 PoC 模式
+    saved_prompts = config.get("saved_prompts", []) or []
     config_dir = get_config_dir()
 
     history_manager = HistoryManager()
@@ -130,6 +131,8 @@ def main():
         history_manager=history_manager,
         auth_bridge=auth_bridge,
         api_key=api_key,
+        saved_prompts=saved_prompts,
+        config_path=config_path,
     )
     history_bridge = HistoryBridge(history_manager=history_manager)
     task_queue_bridge = TaskQueueBridge(task_queue_manager=task_queue_manager)

@@ -264,7 +264,11 @@ Item {
 
                     RowLayout {
                         spacing: App.Theme.space2
-                        SecondaryButton { text: "⭐ 收藏"; enabled: false }
+                        SecondaryButton {
+                            text: "⭐ 收藏"
+                            enabled: promptArea.text.trim().length > 0
+                            onClicked: imageGen.addSavedPrompt(promptArea.text.trim())
+                        }
                         Label {
                             text: "快速选择:"
                             font.family: App.Theme.fontFamily
@@ -274,10 +278,18 @@ Item {
                         ThemedComboBox {
                             id: quickPromptCombo
                             Layout.fillWidth: true
-                            model: ["主石换成闪耀的祖母绿", "改成玫瑰金材质", "增加更多碎钻"]
-                            onActivated: promptArea.text = currentText
+                            model: imageGen.savedPrompts
+                            onActivated: if (currentText) promptArea.text = currentText
+                        }
+                        SecondaryButton {
+                            text: "删除"
+                            enabled: imageGen.savedPrompts.length > 0
+                            onClicked: {
+                                if (quickPromptCombo.currentText) {
+                                    imageGen.removeSavedPrompt(quickPromptCombo.currentText)
+                                }
+                            }
                         }
-                        SecondaryButton { text: "删除"; enabled: false }
                     }
 
                     ScrollView {