feat(pet): move Mochi next to Kira, size +50%

Positioned bottom-right of Kira's bounding box instead of sidebar overlay.
Target size increased from 100px to 150px.

frontend/src/components/Live2DStage.tsx

@@ -35,18 +35,21 @@ function positionKira(kira: any, appW: number, appH: number) {
   kira.position.set(centerMidX, centerMidY);
 }
 
-function positionCat(cat: any) {
-  const el = document.querySelector('[data-petzone]');
-  if (!el || !cat) return;
-  const r = el.getBoundingClientRect();
+function positionCat(cat: any, kira: any, appW: number, appH: number) {
+  if (!cat || !kira) return;
 
-  cat.scale.set(1);
+  // Place Mochi to the bottom-right of Kira
+  const kiraBounds = kira.getBounds();
+  const catTargetPx = 150;
   const naturalH = cat.getLocalBounds().height;
-  const targetPx = 100;
-  const cs = naturalH > 0 ? targetPx / naturalH : 0.05;
+  const cs = naturalH > 0 ? catTargetPx / naturalH : 0.05;
   cat.scale.set(cs);
   cat.anchor.set(0.5, 0.5);
-  cat.position.set(r.left + r.width / 2, r.top + r.height / 2 + 10);
+
+  // Bottom-right of Kira's bounding box, slightly overlapping
+  const offsetX = kiraBounds.width * 0.35;
+  const offsetY = kiraBounds.height * 0.4;
+  cat.position.set(kira.position.x + offsetX, kira.position.y + offsetY);
 }
 
 export default function Live2DStage({ onKiraReady, onReady, outfit, celebrateTrigger }: Props) {
@@ -89,7 +92,7 @@ export default function Live2DStage({ onKiraReady, onReady, outfit, celebrateTri
         const onResize = () => {
           app.renderer.resize(window.innerWidth, window.innerHeight);
           if (kiraModel) positionKira(kiraModel, app.screen.width, app.screen.height);
-          if (catModel) positionCat(catModel);
+          if (catModel) positionCat(catModel, kiraModel, app.screen.width, app.screen.height);
         };
         window.addEventListener('resize', onResize);
 
@@ -118,7 +121,7 @@ export default function Live2DStage({ onKiraReady, onReady, outfit, celebrateTri
           if (!mounted) return;
 
           await new Promise(r => setTimeout(r, 100));
-          positionCat(catModel);
+          positionCat(catModel, kiraModel, app.screen.width, app.screen.height);
           (catModel as any).isInteractive = () => false;
           app.stage.addChild(catModel as any);
           catModelRef.current = catModel;
@@ -438,7 +441,7 @@ export default function Live2DStage({ onKiraReady, onReady, outfit, celebrateTri
         // Resume idle animations
         if (celebratingRef) celebratingRef.current = false;
         // Reset scale
-        positionCat(cat);
+        positionCat(cat, kiraModelRef.current, window.innerWidth, window.innerHeight);
       }
     };