fix: reset WebSocket state when switching projects

Add state reset at the start of the project change effect in
useWebSocket hook. This clears stale progress data, agent status,
and logs when the user switches to a different project, preventing
display of outdated information from the previous project.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

ui/src/hooks/useWebSocket.ts

@@ -125,6 +125,14 @@ export function useProjectWebSocket(projectName: string | null) {
 
   // Connect when project changes
   useEffect(() => {
+    // Reset state when project changes to clear stale data
+    setState({
+      progress: { passing: 0, in_progress: 0, total: 0, percentage: 0 },
+      agentStatus: 'stopped',
+      logs: [],
+      isConnected: false,
+    })
+
     if (!projectName) {
       // Disconnect if no project
       if (wsRef.current) {