fix: exclude dev server from running process check (#736)

When a dev server is running and user sends a message in chat,
the system would throw 'More than one running execution process found'
error because it counted both the dev server and the agent process.

This fix filters out 'devserver' processes from the check, only
considering actual agent processes when determining if multiple
processes are running simultaneously.

frontend/src/hooks/useConversationHistory.ts

@@ -157,10 +157,11 @@ export const useConversationHistory = ({
   };
 
   const getRunningExecutionProcesses = (): ExecutionProcess | null => {
-    // If more than one, throw an error
+    // Filter for running processes, excluding dev server and other non-agent processes
     const runningProcesses = executionProcesses?.current.filter(
-      (p) => p.status === 'running'
+      (p) => p.status === 'running' && p.run_reason !== 'devserver'
     );
+    // Only throw error if there are multiple agent processes running
     if (runningProcesses.length > 1) {
       throw new Error('More than one running execution process found');
     }