feat(updates): check Gitea automatically and deploy on owner confirmation

Add owner-only update controls, a read-only SSH checker and independent systemd deployment services. Build before maintenance; back up code and database; restore on failed deployment. Preserve runtime configuration and gate business writes during the switch.

backend/app/workers/run_knowledge_processor.py

@@ -27,6 +27,8 @@ from pathlib import Path
 # Add the parent directory to Python path to allow imports
 sys.path.append(str(Path(__file__).parent.parent.parent))
 
+from app.core.system_maintenance import wait_for_deployment
+
 from app.workers.knowledge_processor import run_processor
 from app.core.logger import get_logger
 from app.services.firebase import initialize_firebase
@@ -54,6 +56,7 @@ async def run_processor_loop():
         iteration = 0
         
         while True:
+            await wait_for_deployment()
             iteration += 1
             start_time = asyncio.get_event_loop().time()