feat: add NFO scan after rescan and year caching

- Add nfo_scan_after_rescan config option (default: true)
- Implement year caching in AniworldLoader and EnhancedAniWorldLoader
- Make get_year abstract method in base provider
- Run NFO validation/creation after scheduled rescan completes
- Add _YearDict cache to avoid re-extracting year from HTML

src/server/services/scheduler/scheduler_service.py

@@ -11,7 +11,7 @@ from __future__ import annotations
 
 import logging
 from datetime import datetime, timedelta, timezone
-from typing import List, Optional
+from typing import Dict, List, Optional
 
 from apscheduler.schedulers.asyncio import AsyncIOScheduler
 from apscheduler.triggers.cron import CronTrigger
@@ -261,6 +261,9 @@ class SchedulerService:
             "auto_download_after_rescan": (
                 self._config.auto_download_after_rescan if self._config else False
             ),
+            "nfo_scan_after_rescan": (
+                self._config.nfo_scan_after_rescan if self._config else True
+            ),
             "last_run": (
                 self._last_scan_time.isoformat()
                 if self._last_scan_time
@@ -375,7 +378,19 @@ class SchedulerService:
             # 1. Main library rescan
             await self._run_rescan()
 
-            # 2. Auto-download (if enabled)
+            # 2. NFO scan (if enabled)
+            if self._config and self._config.nfo_scan_after_rescan:
+                try:
+                    nfo_result = await self._run_nfo_scan()
+                    await self._broadcast("nfo_scan_started", {
+                        "created": nfo_result.get("created", 0),
+                        "updated": nfo_result.get("updated", 0),
+                    })
+                except Exception as exc:
+                    logger.error("NFO scan failed: %s", exc, exc_info=True)
+                    await self._broadcast("nfo_scan_error", {"error": str(exc)})
+
+            # 3. Auto-download (if enabled)
             if self._config and self._config.auto_download_after_rescan:
                 try:
                     queued = await self._run_auto_download()
@@ -419,6 +434,24 @@ class SchedulerService:
         await anime_service.rescan()
         logger.info("anime_service.rescan() completed")
 
+    async def _run_nfo_scan(self) -> Dict[str, Any]:
+        """Run NFO validation and creation across all series."""
+        from src.server.services.nfo_scan_service import get_nfo_scan_service
+        from src.server.utils.dependencies import get_anime_service
+
+        anime_service = get_anime_service()
+        nfo_scan_service = get_nfo_scan_service()
+
+        logger.info("Starting NFO scan...")
+        result = await nfo_scan_service.scan_all(anime_service)
+        logger.info(
+            "NFO scan completed: created=%d updated=%d errors=%d",
+            result.get("created", 0),
+            result.get("updated", 0),
+            result.get("errors_count", 0),
+        )
+        return result
+
     async def _run_auto_download(self) -> int:
         """Queue and start downloads for all series with missing episodes."""
         from src.server.models.download import EpisodeIdentifier