feat(setup): add SetupService for anime folder initialization

Extract SetupService class from initialization_service to handle:
- Scan data/ folder subdirectories
- Extract title and year from folder names (YYYY pattern)
- Create AnimeSeries records in database
- Resolve provider keys via search (single exact match)

Updates _scan_folders_to_database() to delegate to SetupService.run().
Adds comprehensive unit tests for SetupService.

src/server/services/initialization_service.py

@@ -10,6 +10,7 @@ import structlog
 from src.config.settings import settings
 from src.server.database.service import AnimeSeriesService
 from src.server.services.anime_service import sync_legacy_series_to_db
+from src.server.services.setup_service import SetupService
 
 logger = structlog.get_logger(__name__)
 
@@ -259,7 +260,8 @@ async def _load_series_into_memory(progress_service=None) -> None:
 async def _scan_folders_to_database(progress_service=None) -> int:
     """Scan anime folders and create AnimeSeries DB records.
 
-    This function runs during initial setup only. It:
+    This function runs during initial setup only. It delegates to
+    SetupService.run() which handles:
     1. Iterates subdirectories of anime_directory
     2. Extracts title/year from folder names (year via (YYYY) pattern)
     3. Uses provider search to resolve key field when single match found
@@ -271,9 +273,6 @@ async def _scan_folders_to_database(progress_service=None) -> int:
     Returns:
         int: Number of new series created
     """
-    from src.server.database.connection import get_db_session
-    from src.server.utils.dependencies import get_series_app
-
     logger.info("Scanning anime folders for new series...")
 
     if not settings.anime_directory or not os.path.isdir(settings.anime_directory):
@@ -282,80 +281,12 @@ async def _scan_folders_to_database(progress_service=None) -> int:
         )
         return 0
 
-    created_count = 0
-    skipped_existing = 0
-
-    try:
-        series_app = get_series_app()
-
-        async with get_db_session() as db:
-            for folder in settings.anime_directory.iterdir():
-                if not folder.is_dir():
-                    continue
-
-                folder_name = folder.name
-
-                # Skip if series already exists in DB
-                existing = await AnimeSeriesService.get_by_folder(db, folder_name)
-                if existing:
-                    skipped_existing += 1
-                    continue
-
-                # Extract year from folder name using (YYYY) pattern
-                year = None
-                match = re.search(r'\((\d{4})\)', folder_name)
-                if match:
-                    year = int(match.group(1))
-
-                # Extract title by removing year suffix
-                title = re.sub(r'\s*\(\d{4}\)\s*$', '', folder_name).strip()
-
-                # Try to resolve key via provider search
-                resolved_key = ""
-                if title:
-                    try:
-                        results = await series_app.search(title)
-                        if len(results) == 1:
-                            result_name = results[0].get('name', '').lower()
-                            if result_name == title.lower():
-                                resolved_key = results[0].get('key', '')
-                    except Exception as exc:
-                        logger.warning(
-                            "Provider search failed for folder",
-                            folder=folder_name,
-                            error=str(exc)
-                        )
-
-                # Create AnimeSeries record
-                await AnimeSeriesService.create(
-                    db=db,
-                    key=resolved_key,
-                    name=title,
-                    site=ANIMEWORLD_URL,
-                    folder=folder_name,
-                    year=year,
-                )
-                created_count += 1
-                logger.debug(
-                    "Created series from folder",
-                    folder=folder_name,
-                    title=title,
-                    year=year,
-                    key=resolved_key or "(unresolved)"
-                )
-
-    except Exception as exc:
-        logger.error(
-            "Folder scan failed",
-            error=str(exc),
-            exc_info=True
-        )
-        return created_count
+    # Use SetupService to handle the scanning and creation
+    created_count = await SetupService.run()
 
     logger.info(
         "Folder scan complete",
-        created=created_count,
-        skipped_existing=skipped_existing
+        created=created_count
     )
     return created_count