Add watchlist filesystem reconciliation

http_handler.py

@@ -66,6 +66,7 @@ class HandlerContext:
     http_error: object
     index_html: str
     queue_html: str
+    reconcile_watchlist_downloaded_files: object
     remove_from_watchlist: object
     run_jellyfin_sync: object
     runtime_state: object
@@ -787,6 +788,14 @@ class Handler(BaseHTTPRequestHandler):
                     if str(merged.get(key) or "").strip():
                         Handler.validate_remote_path(self, merged[key], label)
                 self.json(Handler._context(self).start_jellyfin_sync(merged), HTTPStatus.ACCEPTED)
+            elif parsed.path == "/api/config/watchlist/reconcile-downloads":
+                payload = Handler.require_json_object(self, self.body_json())
+                current = Handler._context(self).get_config_snapshot()
+                merged = dict(current)
+                merged.update(payload)
+                if str(merged.get("download_dir") or "").strip():
+                    Handler.validate_remote_path(self, merged["download_dir"], "download directory")
+                self.json(Handler._context(self).reconcile_watchlist_downloaded_files(merged))
             elif parsed.path == "/api/config/webhook/test":
                 payload = Handler.require_json_object(self, self.body_json())
                 validate_discord_webhook_url(payload.get("discord_webhook_url"))