fix: return HTTP 500 instead of calling sys.exit(1) on query errors

Previously, any unhandled exception during query processing caused the
entire backend server to exit via sys.exit(1), making the frontend show
'System offline. Deploy backend first.' until the container was restarted.
Also, is_generating was never reset to False on exception, permanently
blocking all subsequent queries with 429 responses.

- Replace sys.exit(1) with a proper HTTP 500 error response
- Move is_generating = False to the finally block so it always resets

Fixes #382

api.py

@@ -278,8 +278,11 @@ async def process_query(request: QueryRequest):
         return JSONResponse(status_code=200, content=query_resp.jsonify())
     except Exception as e:
         logger.error(f"An error occurred: {str(e)}")
-        sys.exit(1)
+        query_resp.answer = f"An error occurred: {str(e)}"
+        query_resp.reasoning = f"Error: {str(e)}"
+        return JSONResponse(status_code=500, content=query_resp.jsonify())
     finally:
+        is_generating = False
         logger.info("Processing finished")
         if config.getboolean('MAIN', 'save_session'):
             interaction.save_session()

sources/agents/planner_agent.py

@@ -264,8 +264,6 @@ class PlannerAgent(Agent):
         agents_tasks = []
         required_infos = None
         agents_work_result = dict()
-        answer = ""
-        self.stop = False
 
         self.status_message = "Making a plan..."
         agents_tasks = await self.make_plan(goal)