refactor: Clean checkin override parsing and require node type in frontend configuration modal

drb-c2-core/app/internal/mqtt_handler.py

@@ -1,6 +1,6 @@
 import asyncio
 import json
-from datetime import datetime, timezone
+from datetime import datetime, timezone, timedelta
 from typing import Optional
 import paho.mqtt.client as mqtt
 from app.config import settings
@@ -117,14 +117,17 @@ class MQTTHandler:
                     # Approved but not yet configured — restore reachable status after reboot
                     updates["status"] = "unconfigured"
             
-            node_type = payload.get("node_type", existing.get("node_type", "fixed"))
-            enforce_timeout = payload.get("enforce_override_timeout", existing.get("enforce_override_timeout", True))
-            is_overridden = payload.get("is_overridden", False)
-            override_system_id = payload.get("override_system_id")
+            node_type = payload.get("node_type") or existing.get("node_type") or "fixed"
+            enforce_timeout = payload.get("enforce_override_timeout")
+            if enforce_timeout is None:
+                enforce_timeout = existing.get("enforce_override_timeout", True)
             
             updates["node_type"] = node_type
             updates["enforce_override_timeout"] = enforce_timeout
             
+            is_overridden = payload.get("is_overridden", False)
+            override_system_id = payload.get("override_system_id")
+            
             if node_type == "portable":
                 updates["is_overridden"] = False
                 updates["override_system_id"] = None
@@ -138,7 +141,6 @@ class MQTTHandler:
                     existing_override_id = existing.get("override_system_id")
                     if enforce_timeout:
                         if not existing_timeout or existing_override_id != override_system_id:
-                            from datetime import timedelta
                             updates["override_timeout_at"] = (now + timedelta(hours=24)).isoformat()
                     else:
                         updates["override_timeout_at"] = None