Show scan overlay after page reload

- Add is_scanning state tracking in AnimeService
- Add get_scan_status method to AnimeService
- Add /api/anime/scan/status endpoint to check scan state
- Add checkActiveScanStatus in JS to restore overlay on reconnect
- All 1024 tests passing

src/server/api/anime.py

@@ -366,6 +366,31 @@ async def trigger_rescan(
         ) from exc
 
 
+@router.get("/scan/status")
+async def get_scan_status(
+    _auth: dict = Depends(require_auth),
+    anime_service: AnimeService = Depends(get_anime_service),
+) -> dict:
+    """Get the current scan status.
+
+    Returns the current state of any ongoing library scan,
+    useful for restoring UI state after page reload.
+
+    Args:
+        _auth: Ensures the caller is authenticated (value unused)
+        anime_service: AnimeService instance provided via dependency.
+
+    Returns:
+        Dict[str, Any]: Current scan status including:
+            - is_scanning: Whether a scan is in progress
+            - total_items: Total items to scan
+            - directories_scanned: Items scanned so far
+            - current_directory: Current item being scanned
+            - directory: Root scan directory
+    """
+    return anime_service.get_scan_status()
+
+
 class AddSeriesRequest(BaseModel):
     """Request model for adding a new series."""