feat: add legacy key/data file migration to database

- Add migration_legacy_files_completed flag to SystemSettings model
- Create legacy_file_migration service to migrate series from key/data files
- Integrate legacy migration into initialization_service startup flow
- Add integration tests for legacy file migration
- Update DATABASE.md documentation with migration details
- Fix various test and service issues (nfo_repair, tmdb_client, download_service)
- Add test_database_schema unit tests

src/server/services/initialization_service.py

@@ -7,6 +7,7 @@ import structlog
 
 from src.config.settings import settings
 from src.server.services.anime_service import sync_series_from_data_files
+from src.server.services.legacy_file_migration import migrate_series_from_files_to_db
 
 logger = structlog.get_logger(__name__)
 
@@ -99,6 +100,57 @@ async def _mark_initial_scan_completed() -> None:
     )
 
 
+async def _check_legacy_migration_status() -> bool:
+    """Check if legacy key/data file migration has been completed.
+
+    Returns:
+        bool: True if migration was completed, False otherwise
+    """
+    return await _check_scan_status(
+        check_method=lambda svc, db: svc.is_migration_legacy_files_completed(db),
+        scan_type="legacy_migration",
+        log_completed_msg="Legacy file migration already completed, skipping",
+        log_not_completed_msg="Legacy file migration not yet run, will check for files"
+    )
+
+
+async def _mark_legacy_migration_completed() -> None:
+    """Mark the legacy file migration as completed in system settings."""
+    await _mark_scan_completed(
+        mark_method=lambda svc, db: svc.mark_migration_legacy_files_completed(db),
+        scan_type="legacy_migration"
+    )
+
+
+async def _migrate_legacy_files() -> int:
+    """Migrate series from legacy key/data files to database.
+
+    Returns:
+        int: Number of series migrated
+    """
+    from src.server.database.connection import get_db_session
+
+    logger.info("Checking for legacy key/data files to migrate...")
+
+    try:
+        async with get_db_session() as db:
+            migrated_count = await migrate_series_from_files_to_db(
+                settings.anime_directory,
+                db
+            )
+
+        if migrated_count > 0:
+            logger.info("Migrated %d series from legacy files", migrated_count)
+        else:
+            logger.info("No series found in legacy files to migrate")
+
+        return migrated_count
+
+    except Exception as e:
+        logger.warning("Failed to migrate legacy files: %s", e)
+        return 0
+
+
 async def _sync_anime_folders(progress_service=None) -> int:
     """Scan anime folders and sync series to database.
     
@@ -181,18 +233,19 @@ async def _validate_anime_directory(progress_service=None) -> bool:
 
 async def perform_initial_setup(progress_service=None):
     """Perform initial setup including series sync and scan completion marking.
-    
+
     This function is called both during application lifespan startup
     and when the setup endpoint is completed. It ensures that:
-    1. Series are synced from data files to database
-    2. Initial scan is marked as completed
-    3. Series are loaded into memory
-    4. NFO scan is performed if configured
-    5. Media scan is performed
-    
+    1. Legacy key/data files are migrated to database (one-time)
+    2. Series are synced from data files to database
+    3. Initial scan is marked as completed
+    4. Series are loaded into memory
+    5. NFO scan is performed if configured
+    6. Media scan is performed
+
     Args:
         progress_service: Optional ProgressService for emitting updates
-    
+
     Returns:
         bool: True if initialization was performed, False if skipped
     """
@@ -225,17 +278,23 @@ async def perform_initial_setup(progress_service=None):
 
     # Perform the actual initialization
     try:
+        # First, run legacy file migration if needed (independent of initial scan)
+        is_legacy_migration_done = await _check_legacy_migration_status()
+        if not is_legacy_migration_done:
+            await _migrate_legacy_files()
+            await _mark_legacy_migration_completed()
+
         # Sync series from anime folders to database
         await _sync_anime_folders(progress_service)
-        
+
         # Mark the initial scan as completed
         await _mark_initial_scan_completed()
-        
+
         # Load series into memory from database
         await _load_series_into_memory(progress_service)
-        
+
         return True
-        
+
     except (OSError, RuntimeError, ValueError) as e:
         logger.warning("Failed to perform initial setup: %s", e)
         return False