Fix more UME split regressions for sync and alarm WSS.

Restore sql_text and alarm-apply imports, slim WSS handshake headers to accessToken only, and treat 404/503 handshakes as lost subscriptions.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/ume_sync_common.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 from datetime import datetime
 from typing import Any
 
+from sqlalchemy import text as sql_text
 from sqlalchemy.orm import Session
 
 from .models import UmeAlarmCurrent, UmeAlarmHistory, UmeInventoryNE