fix: restore brainstorming feature with missing socket server and real-time events

memento-note/app/api/brainstorm/[sessionId]/manual-idea/route.ts

@@ -177,6 +177,13 @@ export async function POST(
 
     await logActivity(sessionId, 'manual_idea', session.user.id, { ideaTitle: title, ideaId: idea.id })
 
+    await emitToSession(sessionId, 'activity:new', {
+      action: 'manual_idea',
+      userId: session.user.id,
+      userName: session.user.name || 'Guest',
+      details: { ideaTitle: title, ideaId: idea.id }
+    })
+
     await captureSnapshot(sessionId, `Manual idea: ${title}`).catch(() => {})
 
     // [UPDATE - TEMPS RÉEL] Retourner immédiatement, enrichissement IA en arrière-plan