refactor: add folder rename configuration and service

Add configurable folder rename patterns via settings with anime_folder_rename_regex and custom_pattern options. Integrate into SerieScanner and SeriesApp for consistent episode organization.

tests/unit/test_folder_rename_service.py

@@ -455,7 +455,8 @@ class TestValidateAndRenameSeriesFolders:
         assert series_dir.is_dir()
 
     @pytest.mark.asyncio
-    async def test_errors_when_target_exists(self, tmp_path: Path) -> None:
+    async def test_duplicate_target_folder_source_removed_and_db_deleted(self, tmp_path: Path) -> None:
+        """When target folder exists, source folder should be removed and its DB record deleted."""
         anime_dir = tmp_path / "anime"
         anime_dir.mkdir()
         series_dir = anime_dir / "Attack on Titan"
@@ -464,7 +465,13 @@ class TestValidateAndRenameSeriesFolders:
             "<tvshow><title>Attack on Titan</title><year>2013</year></tvshow>"
         )
         # Pre-create the target folder to simulate a duplicate
-        (anime_dir / "Attack on Titan (2013)").mkdir()
+        target_dir = anime_dir / "Attack on Titan (2013)"
+        target_dir.mkdir()
+
+        mock_db = AsyncMock()
+        mock_session = AsyncMock()
+        mock_db.__aenter__.return_value = mock_session
+        mock_db.__aexit__.return_value = None
 
         with patch(
             "src.server.services.folder_rename_service.settings.anime_directory",
@@ -472,14 +479,28 @@ class TestValidateAndRenameSeriesFolders:
         ), patch(
             "src.server.services.folder_rename_service._is_series_being_downloaded",
             return_value=False,
+        ), patch(
+            "src.server.services.folder_rename_service.get_db_session",
+            return_value=mock_db,
+        ), patch(
+            "src.server.services.folder_rename_service.AnimeSeriesService.get_by_key",
+            new_callable=AsyncMock,
+            return_value=None,
+        ), patch(
+            "src.server.services.folder_rename_service.AnimeSeriesService.get_all",
+            new_callable=AsyncMock,
+            return_value=[],
         ):
             stats = await validate_and_rename_series_folders()
 
+        # Source folder removed, target survives
+        assert not series_dir.exists()
+        assert target_dir.is_dir()
+        # Duplicate resolved: counts as renamed (source removed, target kept)
         assert stats["scanned"] == 1
-        assert stats["renamed"] == 0
+        assert stats["renamed"] == 1
         assert stats["skipped"] == 0
-        assert stats["errors"] == 1
-        assert series_dir.is_dir()
+        assert stats["errors"] == 0
 
     @pytest.mark.asyncio
     async def test_counts_multiple_folders(self, tmp_path: Path) -> None:

tests/unit/test_serie_scanner.py

@@ -547,11 +547,31 @@ class TestReadDataFromFile:
 
             scanner = SerieScanner(tmpdir, mock_loader)
             result = scanner._SerieScanner__read_data_from_file("Empty")
-            # Step 4 generates key from folder name when no files exist
+            # Step 5 (was Step 4) generates key from folder name when no files exist
             assert result is not None
             assert isinstance(result, Serie)
             assert result.key == "empty"
 
+    def test_scan_key_override_used_instead_of_generated(self, mock_loader):
+        """Should use override key when folder name matches override dict."""
+        import tempfile
+
+        with tempfile.TemporaryDirectory() as tmpdir:
+            anime_folder = os.path.join(tmpdir, "Anyway, I'm Falling in Love with You (2025)")
+            os.makedirs(anime_folder)
+
+            overrides = {
+                "Anyway, I'm Falling in Love with You (2025)": "anyway-im-falling-in-love-with-you-2025"
+            }
+            scanner = SerieScanner(tmpdir, mock_loader, scan_key_overrides=overrides)
+            result = scanner._SerieScanner__read_data_from_file(
+                "Anyway, I'm Falling in Love with You (2025)"
+            )
+            # Override key should be used instead of generated key
+            assert result is not None
+            assert isinstance(result, Serie)
+            assert result.key == "anyway-im-falling-in-love-with-you-2025"
+
 
 class TestReinit:
     """Test reinit method."""