Refactor Phase 2: Split stories.py into Schema/Service/Controller, add missing endpoints, fix async bug

backend/tests/conftest.py

@@ -121,7 +121,7 @@ def mock_text_provider():
         cover_prompt_suggestion="A cute rabbit",
     )
 
-    with patch("app.api.stories.generate_story_content", new_callable=AsyncMock) as mock:
+    with patch("app.services.story_service.generate_story_content", new_callable=AsyncMock) as mock:
         mock.return_value = mock_result
         yield mock
 
@@ -129,7 +129,7 @@ def mock_text_provider():
 @pytest.fixture
 def mock_image_provider():
     """Mock 图像生成。"""
-    with patch("app.api.stories.generate_image", new_callable=AsyncMock) as mock:
+    with patch("app.services.story_service.generate_image", new_callable=AsyncMock) as mock:
         mock.return_value = "https://example.com/image.png"
         yield mock
 
@@ -137,7 +137,7 @@ def mock_image_provider():
 @pytest.fixture
 def mock_tts_provider():
     """Mock TTS。"""
-    with patch("app.api.stories.text_to_speech", new_callable=AsyncMock) as mock:
+    with patch("app.services.provider_router.text_to_speech", new_callable=AsyncMock) as mock:
         mock.return_value = b"fake-audio-bytes"
         yield mock