fix: prevent duplicate brief submissions, add completion logging

- briefSubmittedRef prevents multiple complete_brief calls
- Added logging throughout completion flow for debugging
- Reset ref on new conversation start

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/components/configurator/VoiceAgentProvider.tsx

@@ -133,6 +133,7 @@ export default function VoiceAgentProvider({ locale, children }: VoiceAgentProvi
   const [completedFormData, setCompletedFormData] = useState<WizardFormData | null>(null);
 
   const turnCompleteRef = useRef(true);
+  const briefSubmittedRef = useRef(false);
   const wsRef = useRef<WebSocket | null>(null);
   const mediaStreamRef = useRef<MediaStream | null>(null);
   const audioContextRef = useRef<AudioContext | null>(null);
@@ -191,6 +192,10 @@ export default function VoiceAgentProvider({ locale, children }: VoiceAgentProvi
       }
 
       if (name === 'complete_brief') {
+        // Prevent duplicate submissions
+        if (briefSubmittedRef.current) return JSON.stringify({ success: true, message: 'Brief already submitted' });
+        briefSubmittedRef.current = true;
+        console.log('[VoiceAgent] complete_brief called, generating...');
         try {
           const formData = { ...DEFAULT_FORM_DATA, ...(args as Partial<WizardFormData>), locale };
           const res = await fetch('/api/configure', {
@@ -199,12 +204,16 @@ export default function VoiceAgentProvider({ locale, children }: VoiceAgentProvi
             body: JSON.stringify(formData),
           });
           const data = (await res.json()) as { success: boolean; brief?: string };
+          console.log('[VoiceAgent] Brief API response:', data.success);
           if (data.success && data.brief) {
             setCompletedBrief(data.brief);
             setCompletedFormData(formData as WizardFormData);
+            console.log('[VoiceAgent] completedBrief and completedFormData set');
           }
-          return JSON.stringify(data);
-        } catch {
+          return JSON.stringify({ success: true });
+        } catch (err) {
+          console.error('[VoiceAgent] Brief generation failed:', err);
+          briefSubmittedRef.current = false;
           return JSON.stringify({ success: false, error: 'Brief generation failed' });
         }
       }
@@ -241,6 +250,7 @@ export default function VoiceAgentProvider({ locale, children }: VoiceAgentProvi
     setSelections({});
     setCompletedBrief(null);
     setCompletedFormData(null);
+    briefSubmittedRef.current = false;
 
     try {
       const tokenRes = await fetch('/api/gemini-token', {