fix(database): decouple worker errors from application

app/schemas/exception.py

@@ -47,6 +47,14 @@ class StorageQueryError(Exception):
     pass
 
 
+class DatabaseWorkerClosedError(RuntimeError):
+    """数据库执行器尚未启动或已经停止。"""
+
+
+class DatabaseWorkerOverloadedError(RuntimeError):
+    """数据库执行器的运行与排队容量已经用尽。"""
+
+
 class TMDbException(Exception):
     """
     用于表示TheMovieDB数据源请求失败的跨层异常契约。

app/schemas/exports.py

@@ -81,6 +81,8 @@ SCHEMA_EXPORTS = {
     'DashboardMemoryInfo': ('app.schemas.dashboard', 'DashboardMemoryInfo'),
     'DashboardSystemInfo': ('app.schemas.dashboard', 'DashboardSystemInfo'),
     'DataT': ('app.schemas.response', 'DataT'),
+    'DatabaseWorkerClosedError': ('app.schemas.exception', 'DatabaseWorkerClosedError'),
+    'DatabaseWorkerOverloadedError': ('app.schemas.exception', 'DatabaseWorkerOverloadedError'),
     'Dict': ('app.schemas.mcp', 'Dict'),
     'DiscoverMediaSource': ('app.schemas.event', 'DiscoverMediaSource'),
     'DiscoverSourceEventData': ('app.schemas.event', 'DiscoverSourceEventData'),