fix(search): 支持单次搜索启用多个媒体数据源，合并显示所有源结果 (#6270)

- 新增 is_media_source_enabled/is_media_source_selected，请求级 source 支持逗号分隔多数据源，缺省回退全局 SEARCH_SOURCE 配置
- 四个媒体模块的搜索/人物/合集方法统一接入多源判断
- 补充多数据源搜索相关测试

tests/test_media_search_source_selection.py

@@ -7,6 +7,7 @@ from app.api.endpoints.media import search
 from app.chain import ChainBase
 from app.modules.douban import DoubanModule
 from app.modules.themoviedb import TheMovieDbModule
+from app.schemas.types import MediaType
 
 
 @pytest.mark.parametrize(
@@ -38,6 +39,27 @@ def test_media_search_endpoint_forwards_source(
     search_method.assert_awaited_once_with(name="测试", source=source)
 
 
+def test_media_search_endpoint_forwards_multi_source() -> None:
+    """媒体搜索接口应将逗号分隔的多数据源原样下传到处理链。"""
+    chain = Mock()
+    chain.async_search = AsyncMock(return_value=(Mock(), []))
+
+    with patch("app.api.endpoints.media.MediaChain", return_value=chain):
+        result = asyncio.run(
+            search(
+                title="测试",
+                type="media",
+                source="themoviedb,douban",
+                _=Mock(),
+            )
+        )
+
+    assert result == []
+    chain.async_search.assert_awaited_once_with(
+        title="测试", source="themoviedb,douban"
+    )
+
+
 @pytest.mark.parametrize(
     ("method_name", "module_method_name"),
     [
@@ -120,3 +142,72 @@ def test_tmdb_collection_search_rejects_unsupported_source() -> None:
 
     assert result is None
     module.tmdb.async_search_collections.assert_not_awaited()
+
+
+def test_tmdb_collection_search_supports_multi_source_request() -> None:
+    """TMDB合集搜索应支持请求级逗号分隔多数据源。"""
+    module = TheMovieDbModule()
+    module.tmdb = Mock()
+    module.tmdb.async_search_collections = AsyncMock(return_value=[])
+
+    result = asyncio.run(
+        module.async_search_collections(
+            name="测试", source="themoviedb,douban"
+        )
+    )
+
+    assert result == []
+    module.tmdb.async_search_collections.assert_awaited_once_with("测试")
+
+
+def test_tmdb_media_search_supports_multi_source_request(monkeypatch) -> None:
+    """TMDB媒体搜索应支持请求级逗号分隔多数据源，不被其他来源请求阻断。"""
+    monkeypatch.setattr("app.modules.themoviedb.settings.SEARCH_SOURCE", "douban")
+    module = TheMovieDbModule()
+    module.tmdb = Mock()
+    module.tmdb.search_multiis = Mock(return_value=[])
+    meta = Mock()
+    meta.name = "测试"
+    meta.type = MediaType.UNKNOWN
+    meta.year = None
+
+    skipped = module.search_medias(meta=meta, source="douban")
+    result = module.search_medias(meta=meta, source="themoviedb,douban")
+
+    assert skipped is None
+    assert result == []
+    module.tmdb.search_multiis.assert_called_once_with("测试")
+
+
+def test_douban_media_search_supports_multi_source_request(monkeypatch) -> None:
+    """豆瓣媒体搜索应支持请求级逗号分隔多数据源，并跟随全局配置参与搜索。"""
+    monkeypatch.setattr("app.modules.douban.settings.SEARCH_SOURCE", "themoviedb")
+    module = DoubanModule()
+    module.doubanapi = Mock()
+    module.doubanapi.async_search = AsyncMock(return_value={"items": []})
+    meta = Mock()
+    meta.name = "测试"
+
+    result = asyncio.run(
+        module.async_search_medias(meta=meta, source="themoviedb,douban")
+    )
+
+    assert result == []
+    module.doubanapi.async_search.assert_awaited_once_with("测试")
+
+
+def test_multi_source_request_keeps_missing_module_skipped(monkeypatch) -> None:
+    """请求级多数据源未包含的模块应跳过，避免无关模块参与搜索。"""
+    monkeypatch.setattr("app.modules.douban.settings.SEARCH_SOURCE", "themoviedb")
+    module = DoubanModule()
+    module.doubanapi = Mock()
+    module.doubanapi.async_search = AsyncMock(return_value={"items": []})
+    meta = Mock()
+    meta.name = "测试"
+
+    skipped = asyncio.run(
+        module.async_search_medias(meta=meta, source="themoviedb")
+    )
+
+    assert skipped is None
+    module.doubanapi.async_search.assert_not_awaited()