Implement initial NFO scan tracking for one-time setup

- Add NFO scanning to startup process (fastapi_app.py)
- Check initial_nfo_scan_completed flag before running NFO scan
- Run NFO scan only on first startup if TMDB API key is configured
- Mark NFO scan as completed after first successful run
- Skip NFO scan on subsequent startups

This ensures NFO metadata processing only occurs during initial setup,
not on every application restart, improving startup performance.

src/server/fastapi_app.py

@@ -256,6 +256,70 @@ async def lifespan(_application: FastAPI):
                 await anime_service._load_series_from_db()
                 logger.info("Series loaded from database into memory")
                 
+                # Check if initial NFO scan has been completed
+                try:
+                    async with get_db_session() as db:
+                        is_nfo_scan_done = (
+                            await SystemSettingsService
+                            .is_initial_nfo_scan_completed(db)
+                        )
+                except Exception as e:
+                    logger.warning(
+                        "Failed to check NFO scan status: %s, assuming not done",
+                        e
+                    )
+                    is_nfo_scan_done = False
+                
+                # Run NFO scan only on first run (if configured)
+                if settings.tmdb_api_key and (
+                    settings.nfo_auto_create or settings.nfo_update_on_scan
+                ):
+                    if not is_nfo_scan_done:
+                        logger.info("Performing initial NFO scan...")
+                        try:
+                            from src.core.services.series_manager_service import (
+                                SeriesManagerService,
+                            )
+                            
+                            manager = SeriesManagerService.from_settings()
+                            await manager.scan_and_process_nfo()
+                            await manager.close()
+                            logger.info("Initial NFO scan completed")
+                            
+                            # Mark NFO scan as completed
+                            try:
+                                async with get_db_session() as db:
+                                    await (
+                                        SystemSettingsService
+                                        .mark_initial_nfo_scan_completed(db)
+                                    )
+                                logger.info("Marked NFO scan as completed")
+                            except Exception as e:
+                                logger.warning(
+                                    "Failed to mark NFO scan as completed: %s",
+                                    e
+                                )
+                        except Exception as e:
+                            logger.error(
+                                "Failed to complete NFO scan: %s",
+                                e,
+                                exc_info=True
+                            )
+                    else:
+                        logger.info(
+                            "Skipping NFO scan - already completed on previous run"
+                        )
+                else:
+                    if not settings.tmdb_api_key:
+                        logger.info(
+                            "NFO scan skipped - TMDB API key not configured"
+                        )
+                    else:
+                        logger.info(
+                            "NFO scan skipped - auto_create and update_on_scan "
+                            "both disabled"
+                        )
+                
                 # Now initialize download service (will use data from database)
                 from src.server.utils.dependencies import get_download_service
                 download_service = get_download_service()