fix(frontend): recover startup and discard stale reasoning answers

vocero-frontend/src/components/VoiceStage.tsx

@@ -119,8 +119,10 @@ export function VoiceStage({ state, controller }: { state: AppState; controller:
   const live = LIVE_STATES.has(state.status);
   const active = ACTIVE_STATES.has(state.status);
   const status = state.status === "closed" ? "idle" : state.status;
-  const caption =
-    state.muted && (status === "listening" || status === "user-speaking")
+  const ready = state.configReady && !state.contextLoading;
+  const caption = !ready
+    ? "Preparando contexto…"
+    : state.muted && (status === "listening" || status === "user-speaking")
       ? "Micrófono silenciado"
       : CAPTIONS[state.status];
   const label = active
@@ -136,7 +138,7 @@ export function VoiceStage({ state, controller }: { state: AppState; controller:
       void controller.start();
     }
   };
-  const disabled = active && status !== "your-turn";
+  const disabled = !ready || (active && status !== "your-turn");
   return (
     <main className="stage">
       {white ? (