fix: complete OPC system implementation

- Add database connection retry logic (3 attempts, 5s delay)
- Add missing database functions: get_task_by_id, get_agent_execution, approve_agent_execution, update_agent_config, update_execution_status
- Complete agent execution approval workflow
- Fix agent executor to handle approved executions
- Fix inefficient task queries (use direct ID lookup)
- Add error action handling in agent executor
- Improve LiteLLM error handling with specific exception types
- Reduce LiteLLM timeout from 60s to 30s
- Fix execution status update to only set started_at once
- Consolidate WebSocket datetime serialization with helper function
- Implement update agent endpoint

dashboard/backend/services/agents/base_agent.py

@@ -76,6 +76,9 @@ Only propose actions you can actually execute. Be specific and actionable."""
 
     async def _call_llm(self, prompt: str) -> str:
         """Call LiteLLM proxy"""
+        import logging
+        logger = logging.getLogger(__name__)
+
         model = self.config.get("model", "claude-sonnet-4-6")
         temperature = self.config.get("temperature", 0.7)
 
@@ -85,7 +88,7 @@ Only propose actions you can actually execute. Be specific and actionable."""
             if self.litellm_api_key and self.litellm_api_key.strip():
                 headers["Authorization"] = f"Bearer {self.litellm_api_key}"
 
-            async with httpx.AsyncClient(timeout=60.0) as client:
+            async with httpx.AsyncClient(timeout=30.0) as client:
                 response = await client.post(
                     f"{self.litellm_url}/chat/completions",
                     headers=headers,
@@ -102,7 +105,17 @@ Only propose actions you can actually execute. Be specific and actionable."""
                 response.raise_for_status()
                 data = response.json()
                 return data["choices"][0]["message"]["content"]
+        except httpx.ConnectError as e:
+            logger.error(f"LiteLLM connection failed: {e}")
+            raise Exception(f"LiteLLM service unavailable: {str(e)}")
+        except httpx.TimeoutException as e:
+            logger.error(f"LiteLLM request timeout: {e}")
+            raise Exception(f"LiteLLM request timeout: {str(e)}")
+        except httpx.HTTPStatusError as e:
+            logger.error(f"LiteLLM HTTP error: {e.response.status_code} - {e.response.text}")
+            raise Exception(f"LiteLLM HTTP error {e.response.status_code}: {e.response.text}")
         except Exception as e:
+            logger.error(f"LiteLLM call failed: {e}")
             raise Exception(f"LLM call failed: {str(e)}")
 
     def _parse_response(self, response: str) -> Dict[str, Any]: