Rename sync_series_from_data_files to sync_legacy_series_to_db

- Rename function to reflect its legacy status
- Add deprecation warning log on execution
- Update all callers (initialization_service, api/config, fastapi_app)
- Update tests to use new name
- Add deprecation notice to DEVELOPMENT.md

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/integration/test_end_to_end_workflows.py

@@ -21,7 +21,7 @@ class TestInitializationWorkflow:
     async def test_perform_initial_setup_with_mocked_dependencies(self):
         """Test initial setup completes with minimal mocking."""
         # Mock only the external dependencies
-        with patch('src.server.services.anime_service.sync_series_from_data_files') as mock_sync:
+        with patch('src.server.services.anime_service.sync_legacy_series_to_db') as mock_sync:
             mock_sync.return_value = 0  # No series to sync
             
             # Call the actual function
@@ -241,9 +241,9 @@ class TestModuleStructure:
         assert hasattr(initialization_service, 'settings')
     
     def test_sync_series_function_imported(self):
-        """Test sync_series_from_data_files is imported."""
-        assert hasattr(initialization_service, 'sync_series_from_data_files')
-        assert callable(initialization_service.sync_series_from_data_files)
+        """Test sync_legacy_series_to_db is imported."""
+        assert hasattr(initialization_service, 'sync_legacy_series_to_db')
+        assert callable(initialization_service.sync_legacy_series_to_db)
 
 
 # Simpler integration tests that don't require complex mocking
@@ -413,7 +413,7 @@ class TestInitialSetupWorkflow:
     async def test_initial_setup_already_completed(self):
         """Test initial setup when already completed."""
         with patch.object(initialization_service, '_check_initial_scan_status', return_value=True), \
-             patch('src.server.services.anime_service.sync_series_from_data_files'):
+             patch('src.server.services.anime_service.sync_legacy_series_to_db'):
             
             result = await initialization_service.perform_initial_setup()
             
@@ -425,7 +425,7 @@ class TestInitialSetupWorkflow:
         """Test initial setup with no directory configured."""
         with patch.object(initialization_service, '_check_initial_scan_status', return_value=False), \
              patch.object(initialization_service, '_validate_anime_directory', return_value=False), \
-             patch('src.server.services.anime_service.sync_series_from_data_files'):
+             patch('src.server.services.anime_service.sync_legacy_series_to_db'):
             
             result = await initialization_service.perform_initial_setup()
             
@@ -440,7 +440,7 @@ class TestInitialSetupWorkflow:
              patch.object(initialization_service, '_sync_anime_folders', return_value=5), \
              patch.object(initialization_service, '_mark_initial_scan_completed'), \
              patch.object(initialization_service, '_load_series_into_memory'), \
-             patch('src.server.services.anime_service.sync_series_from_data_files'):
+             patch('src.server.services.anime_service.sync_legacy_series_to_db'):
             
             mock_progress = AsyncMock()
             result = await initialization_service.perform_initial_setup(mock_progress)
@@ -456,7 +456,7 @@ class TestInitialSetupWorkflow:
         with patch.object(initialization_service, '_check_initial_scan_status', return_value=False), \
              patch.object(initialization_service, '_validate_anime_directory', return_value=True), \
              patch.object(initialization_service, '_sync_anime_folders', side_effect=OSError("Disk error")), \
-             patch('src.server.services.anime_service.sync_series_from_data_files'):
+             patch('src.server.services.anime_service.sync_legacy_series_to_db'):
             
             result = await initialization_service.perform_initial_setup()
             
@@ -469,7 +469,7 @@ class TestInitialSetupWorkflow:
         with patch.object(initialization_service, '_check_initial_scan_status', return_value=False), \
              patch.object(initialization_service, '_validate_anime_directory', return_value=True), \
              patch.object(initialization_service, '_sync_anime_folders', side_effect=RuntimeError("DB error")), \
-             patch('src.server.services.anime_service.sync_series_from_data_files'):
+             patch('src.server.services.anime_service.sync_legacy_series_to_db'):
             
             result = await initialization_service.perform_initial_setup()