feat: agent resources upgrade

backend/src/app_mixins/agent.py

@@ -126,13 +126,21 @@ class AgentMixin:
 
     async def save_agent_resource(self, agent_id, kind, key, value):
         await db.AgentResource.update_or_create(
+            {'value': value},
             agent_id=agent_id,
             kind=kind,
             key=key,
-            value=value,
         )
         print(f"Saved agent resource: {agent_id} - {kind} - {key}")
 
+    async def delete_agent_resource(self, agent_id, kind, key):
+        await db.AgentResource.filter(
+            agent_id=agent_id,
+            kind=kind,
+            key=key,
+        ).delete()
+        print(f"Deleted agent resource: {agent_id} - {kind} - {key}")
+
     # --- Control & Actions ---
 
     async def get_agent_control(self, agent_id):