feat: deeper discovery questions + conversation summary in briefs

- Agent now asks probing follow-up questions (pain points, current tools, vision, decision context)
- complete_brief tool includes conversationSummary field capturing ALL discussion details
- Summary merges into scope context for richer, more targeted briefs
- Updated both EN and FR system prompts

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

src/components/configurator/VoiceAgentProvider.tsx

@@ -200,7 +200,12 @@ export default function VoiceAgentProvider({ locale, children }: VoiceAgentProvi
         setIsGeneratingBrief(true);
         console.log('[VoiceAgent] complete_brief called, generating...');
         try {
-          const formData = { ...DEFAULT_FORM_DATA, ...(args as Partial<WizardFormData>), locale };
+          const toolArgs = args as Partial<WizardFormData> & { conversationSummary?: string };
+          const summary = toolArgs.conversationSummary ?? '';
+          const existingScope = toolArgs.scope ?? '';
+          const combinedScope = [existingScope, summary].filter(Boolean).join('\n\n');
+          const formData = { ...DEFAULT_FORM_DATA, ...toolArgs, scope: combinedScope, locale };
+          delete (formData as Record<string, unknown>).conversationSummary;
           const res = await fetch('/api/configure', {
             method: 'POST',
             headers: { 'Content-Type': 'application/json' },