fix(webgl): use forceCanvas for Live2DCat to avoid dual WebGL context conflicts

Reverts shared-context approach. Live2DCat gets its own canvas with
forceCanvas:true (Canvas2D renderer), which avoids the WebGL bindBuffer
spam entirely. Cleaned up onAppReady prop from KiraAvatar.

frontend/src/App.tsx

@@ -33,7 +33,6 @@ export default function App() {
   const [currentOutfit, setCurrentOutfit] = useState('cozy-hoodie');
   const [currentAcc, setCurrentAcc] = useState<string | null>(null);
   const [textInput, setTextInput] = useState('');
-  const [pixiApp, setPixiApp] = useState<any>(null);
 
   useEffect(() => {
     if (preferences.scene) setCurrentSceneId(preferences.scene);
@@ -148,7 +147,6 @@ export default function App() {
               outfit={currentOutfit}
               accessory={currentAcc}
               onTalkToggle={handleTalkToggle}
-              onAppReady={setPixiApp}
             />
           </div>
 
@@ -157,7 +155,7 @@ export default function App() {
             <MusicPlayer />
             <WhiteNoise />
             <Wardrobe onOutfitChange={handleOutfitChange} onAccessoryChange={handleAccessoryChange} />
-            <PetZone app={pixiApp} />
+            <PetZone />
           </div>
         </div>
 

frontend/src/components/KiraAvatar.tsx

@@ -7,7 +7,6 @@ interface Props {
   outfit: string;
   accessory: string | null;
   onTalkToggle: () => void;
-  onAppReady?: (app: any) => void;
 }
 
 type ExpressionName = 'Normal' | 'Smile' | 'Sad' | 'Angry' | 'Surprised' | 'Blushing';
@@ -82,8 +81,7 @@ export default function KiraAvatar(props: Props) {
 
         app.stage.addChild(model as any);
         (model as any).isInteractive = () => false;
-
-        if (props.onAppReady) props.onAppReady(app);
+        if (!mounted) return;
 
         try {
           textureRef.current = {

frontend/src/components/Live2DCat.tsx

@@ -1,42 +1,58 @@
 import { useEffect, useRef } from 'react';
 
 interface Props {
-  app: any;
   className?: string;
 }
 
-export default function Live2DCat({ app, className }: Props) {
-  const modelRef = useRef<any>(null);
+export default function Live2DCat({ className }: Props) {
+  const canvasRef = useRef<HTMLCanvasElement>(null);
 
   useEffect(() => {
-    if (!app) return;
     let mounted = true;
+    const canvas = canvasRef.current;
+    if (!canvas) return;
+
+    let app: any = null;
 
     const init = async () => {
       try {
+        const { Application, Ticker } = await import('pixi.js');
         const { Live2DModel } = await import('pixi-live2d-display/cubism4');
+        (Live2DModel as any).registerTicker(Ticker as any);
+
+        const w = canvas.clientWidth || 120;
+        const h = canvas.clientHeight || 120;
+
+        // forceCanvas avoids WebGL context conflicts with KiraAvatar's context
+        app = new Application({
+          view: canvas,
+          width: w,
+          height: h,
+          antialias: true,
+          resolution: Math.min(window.devicePixelRatio || 1, 2),
+          backgroundAlpha: 0,
+          autoDensity: true,
+          forceCanvas: true,
+        });
+        if (!mounted) { app.destroy(true); return; }
 
         const model = await Live2DModel.from('/live2d/models/little-cat/LittleCat.model3.json', {
           autoInteract: false,
         });
-        if (!mounted) return;
+        if (!mounted) { app.destroy(true); return; }
 
-        // Scale to fit ~120x120 area on the shared stage
         const sw = app.screen.width;
         const sh = app.screen.height;
-        const targetW = 120;
-        const targetH = 120;
-        const s = Math.min(targetW / model.width, targetH / model.height);
+        const s = Math.min((sw * 0.85) / model.width, (sh * 0.85) / model.height);
         model.scale.set(s);
         model.anchor.set(0.5, 0.5);
-        // Position near top-left corner with some padding
-        model.position.set(80, 80);
+        model.position.set(sw / 2, sh / 2);
 
         app.stage.addChild(model as any);
         (model as any).isInteractive = () => false;
-        modelRef.current = model;
 
         try { model.motion('Idle'); } catch { /* */ }
+
       } catch (e) {
         console.warn('[Live2DCat]', e);
       }
@@ -46,14 +62,15 @@ export default function Live2DCat({ app, className }: Props) {
 
     return () => {
       mounted = false;
-      if (modelRef.current) {
-        app.stage.removeChild(modelRef.current);
-        modelRef.current.destroy?.();
-        modelRef.current = null;
-      }
+      if (app) { app.destroy(true, { children: true }); }
     };
-  }, [app]);
+  }, []);
 
-  // Live2DCat no longer renders its own canvas — it shares the KiraAvatar canvas
-  return null;
+  return (
+    <canvas
+      ref={canvasRef}
+      className={className}
+      style={{ display: 'block' }}
+    />
+  );
 }

frontend/src/components/PetZone.tsx

@@ -1,10 +1,6 @@
 import Live2DCat from './Live2DCat';
 
-interface Props {
-  app: any;
-}
-
-export default function PetZone({ app }: Props) {
+export default function PetZone() {
   return (
     <div className="p-4 relative overflow-hidden" style={{ minHeight: 140 }}>
       <h3 className="text-sm font-bold text-kira-plum mb-2 flex items-center gap-2">
@@ -12,8 +8,7 @@ export default function PetZone({ app }: Props) {
       </h3>
       <div className="flex items-center justify-center">
         <div className="flex flex-col items-center">
-          {/* Cat model is rendered on the shared KiraAvatar canvas */}
-          <Live2DCat app={app} />
+          <Live2DCat className="w-28 h-28" />
           <span className="text-[10px] text-kira-plum/60 mt-1 font-medium">Mochi</span>
         </div>
       </div>