feat(ui): display livePartial / transcript_delta in ChatBubble as 'Hearing:' indicator

- REST STT now sends delta (full text) so UI lights up immediately with what was heard.
- Works as 'live' for the final transcript (true partials would stream words if Realtime was available).
- Per PLAN item 3.

frontend/src/App.tsx

@@ -28,6 +28,7 @@ export default function App() {
     sendText,
     startRecording,
     stopRecording,
+    livePartial,
   } = useConversation();
 
   const [currentSceneId, setCurrentSceneId] = useState('cozy-room');
@@ -143,7 +144,7 @@ export default function App() {
 
             {/* Column 3: Chat + Text Input */}
             <div className="space-y-4">
-              <ChatBubble messages={messages} isKiraSpeaking={isKiraSpeaking} userName={userName} />
+              <ChatBubble messages={messages} isKiraSpeaking={isKiraSpeaking} userName={userName} livePartial={livePartial} />
 
               {/* Text input fallback */}
               <div className="glass-card p-3">

frontend/src/components/ChatBubble.tsx

@@ -11,9 +11,10 @@ interface Props {
   messages: Message[];
   isKiraSpeaking: boolean;
   userName?: string;
+  livePartial?: string;
 }
 
-export default function ChatBubble({ messages, isKiraSpeaking }: Props) {
+export default function ChatBubble({ messages, isKiraSpeaking, livePartial }: Props) {
   const bottomRef = useRef<HTMLDivElement>(null);
 
   useEffect(() => {
@@ -27,6 +28,15 @@ export default function ChatBubble({ messages, isKiraSpeaking }: Props) {
         <span className={`w-2 h-2 rounded-full ${isKiraSpeaking ? 'bg-kira-pink animate-pulse' : 'bg-kira-mint'}`} />
       </h3>
 
+      {livePartial && (
+        <div className="mb-2 px-3 py-1.5 bg-kira-lav/20 text-kira-plum/70 text-xs rounded-xl flex items-center gap-2">
+          <span>👂</span>
+          <span className="font-medium">Hearing:</span>
+          <span className="truncate">{livePartial}</span>
+          <span className="animate-pulse">...</span>
+        </div>
+      )}
+
       <div className="flex-1 overflow-y-auto space-y-2 scrollbar-thin pr-1">
         {messages.length === 0 && (
           <div className="text-xs text-kira-plum/30 text-center py-6">

frontend/src/hooks/useConversation.ts

@@ -39,6 +39,7 @@ export function useConversation() {
   });
   const [loadingPrefs, setLoadingPrefs] = useState(true);
   const [micError, setMicError] = useState<string | null>(null);
+  const [livePartial, setLivePartial] = useState<string>('');
 
   const wsRef = useRef<WebSocket | null>(null);
   const audioRef = useRef<HTMLAudioElement | null>(null);
@@ -109,7 +110,11 @@ export function useConversation() {
         break;
 
       case 'transcript_delta':
-        // Streaming partial transcript — could show as typing indicator
+        if (msg.text) {
+          setLivePartial(msg.text);
+          // Clear after short delay so it doesn't stick (for REST full-text case)
+          setTimeout(() => setLivePartial(''), 1500);
+        }
         break;
 
       case 'speaking_start':
@@ -282,6 +287,7 @@ export function useConversation() {
     preferences,
     loadingPrefs,
     micError,
+    livePartial,
     identify,
     setPreference,
     sendText,