feat(ui): center avatar as hero, ~1/3 viewport height; tools grid below

- Avatar now centered in its own row above the tools grid (was crammed in column 1)
- KiraAvatar container: min-height 33vh, canvas up to 500px wide
- Tools reorganized into 4 columns below: Chat, Timer+Music, Notes+Noise, Clock+Pets+Wardrobe
- WelcomeScreen restored to full (not compact) for first-time users

frontend/src/App.tsx

@@ -80,7 +80,7 @@ export default function App() {
   if (!identified && !loadingPrefs) {
     const savedId = localStorage.getItem('kira-user-id');
     if (!savedId) {
-      return <WelcomeScreen onComplete={handleWelcome} isCompact />;
+      return <WelcomeScreen onComplete={handleWelcome} />;
     }
     // Has saved ID but not identified yet — show welcome with their name
     return (
@@ -121,13 +121,9 @@ export default function App() {
           <Toolbar currentScene={currentSceneId} onSceneChange={handleSceneChange} />
         </div>
 
-        {/* Main grid */}
-        <div className="flex-1 overflow-y-auto px-4 py-4 scrollbar-thin">
-          <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4 max-w-7xl mx-auto">
-
-            {/* Column 1: Kira + Clock */}
-            <div className="space-y-4">
-              <Clock />
+        {/* Hero: Avatar centered, ~1/3 of viewport */}
+        <div className="flex-none flex justify-center py-4 px-4">
+          <div className="w-full max-w-md">
             <KiraAvatar
               isSpeaking={isKiraSpeaking}
               isListening={isRecording}
@@ -136,22 +132,18 @@ export default function App() {
               onTalkToggle={handleTalkToggle}
             />
           </div>
-
-            {/* Column 2: Timer + Music + Notes + WhiteNoise */}
-            <div className="space-y-4">
-              <Timer />
-              <MusicPlayer />
-              <Notes />
-              <WhiteNoise />
         </div>
 
-            {/* Column 3: Chat + Text Input */}
+        {/* Tools grid below the avatar */}
+        <div className="flex-1 overflow-y-auto px-4 pb-4 scrollbar-thin">
+          <div className="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 gap-4 max-w-7xl mx-auto">
+
+            {/* Column 1: Chat + Text Input */}
             <div className="space-y-4">
               <ChatBubble messages={messages} isKiraSpeaking={isKiraSpeaking} userName={userName} livePartial={livePartial} />
 
               {/* Text input fallback */}
               <div className="glass-card p-3">
-                {/* Subtle greeting */}
                 <div className="text-[10px] text-kira-plum/30 mb-2">
                   hey {userName} ✨
                 </div>
@@ -174,8 +166,21 @@ export default function App() {
               </div>
             </div>
 
-            {/* Column 4: Cats + Wardrobe */}
+            {/* Column 2: Timer + Music */}
             <div className="space-y-4">
+              <Timer />
+              <MusicPlayer />
+            </div>
+
+            {/* Column 3: Notes + White Noise */}
+            <div className="space-y-4">
+              <Notes />
+              <WhiteNoise />
+            </div>
+
+            {/* Column 4: Cats + Wardrobe + Clock */}
+            <div className="space-y-4">
+              <Clock />
               <PetZone />
               <Wardrobe onOutfitChange={handleOutfitChange} onAccessoryChange={handleAccessoryChange} />
             </div>

frontend/src/components/KiraAvatar.tsx

@@ -55,8 +55,9 @@ export default function KiraAvatar(props: Props) {
         // Cast needed due to pixi-live2d-display expecting older Ticker type
         (Live2DModel as any).registerTicker(Ticker as any);
 
-        // Responsive sizing
-        const size = Math.min(container.clientWidth || 260, 260);
+        // Responsive sizing — fill the container, target ~1/3 viewport
+        const containerW = container.clientWidth || 400;
+        const size = Math.min(containerW, 500);
         const app = new Application({
           width: size,
           height: size * 1.25,
@@ -198,12 +199,12 @@ export default function KiraAvatar(props: Props) {
   }, [props.accessory, live2dReady]);
 
   return (
-    <div className="glass-card p-4 flex flex-col items-center" style={{ minHeight: 360 }}>
+    <div className="glass-card p-6 flex flex-col items-center w-full" style={{ minHeight: '33vh' }}>
       {/* Live2D canvas */}
       <div
         ref={canvasRef}
         className={`relative w-full ${live2dReady ? 'block' : 'hidden'}`}
-        style={{ maxWidth: 260, height: 325 }}
+        style={{ maxWidth: 500, height: '30vh', minHeight: 250 }}
       />
 
       {/* SVG fallback */}