fix(avatar): re-apply CSS 100% after Pixi resize(); use fitModel helper; 65% margin

Pixi renderer.resize() overwrites canvas inline width/height styles,
locking the canvas to the initial size and leaving empty space below.
Now we re-apply width:100%;height:100% after every resize so the canvas
always fills its container. Removed unused appRef.

frontend/src/components/KiraAvatar.tsx

@@ -24,7 +24,6 @@ const OUTFIT_TEXTURES: Record<string, string> = {
 
 export default function KiraAvatar(props: Props) {
   const canvasRef = useRef<HTMLDivElement>(null);
-  const appRef = useRef<any>(null);
   const modelRef = useRef<any>(null);
   const textureRef = useRef<any>(null);
   const lipSyncRef = useRef<number>(0);
@@ -41,6 +40,16 @@ export default function KiraAvatar(props: Props) {
 
     let app: any = null;
     let model: any = null;
+    let canvasEl: HTMLCanvasElement | null = null;
+
+    const fitModel = (crW: number, crH: number) => {
+      if (!model || !app) return;
+      const maxW = crW * 0.65;
+      const maxH = crH * 0.65;
+      const s = Math.min(maxW / model.width, maxH / model.height);
+      model.scale.set(s);
+      model.position.set(app.screen.width / 2, app.screen.height / 2);
+    };
 
     const init = async () => {
       try {
@@ -73,6 +82,7 @@ export default function KiraAvatar(props: Props) {
         canvas.style.height = '100%';
         canvas.style.display = 'block';
         container.appendChild(canvas);
+        canvasEl = canvas;
 
         model = await Live2DModel.from('/live2d/models/kira/kira.model3.json', {
           autoInteract: false,
@@ -80,8 +90,8 @@ export default function KiraAvatar(props: Props) {
         modelRef.current = model;
 
         // Fit model with generous margin to avoid clipping
-        const maxW = w * 0.68;
-        const maxH = h * 0.68;
+        const maxW = w * 0.65;
+        const maxH = h * 0.65;
         const scale = Math.min(maxW / model.width, maxH / model.height);
         model.scale.set(scale);
         model.anchor.set(0.5, 0.5);
@@ -117,17 +127,16 @@ export default function KiraAvatar(props: Props) {
 
     // Use ResizeObserver so we init with the real laid-out size
     const ro = new ResizeObserver((entries) => {
+      const cr = entries[0].contentRect;
       if (app) {
         // Already init'd — handle resize
-        const cr = entries[0].contentRect;
         app.renderer.resize(Math.round(cr.width), Math.round(cr.height));
-        if (model) {
-          const maxW = cr.width * 0.68;
-          const maxH = cr.height * 0.68;
-          const s = Math.min(maxW / model.width, maxH / model.height);
-          model.scale.set(s);
-          model.position.set(app.screen.width / 2, app.screen.height / 2);
+        // Re-apply CSS 100% because Pixi resize() overwrites inline styles
+        if (canvasEl) {
+          canvasEl.style.width = '100%';
+          canvasEl.style.height = '100%';
         }
+        fitModel(cr.width, cr.height);
         return;
       }
       // First measurement — run init