复用胶囊标签收口画布尺寸提示

画布图片 hover 尺寸标签改为复用 PlatformPillBadge，统一覆盖层 badge 基础结构。

删除尺寸标签局部圆角、字号和排版样式，仅保留画布内定位与深色覆盖。

补充编辑器测试覆盖共享胶囊标签 class，并更新 TRACKING。

src/components/image-editor/ImageCanvasEditorView.test.tsx

@@ -479,7 +479,9 @@ describe('ImageCanvasEditorView', () => {
     const canvasImage = screen.getByAltText('画布图片：拼图素材');
     fireEvent.mouseEnter(canvasImage.closest('button')!);
 
-    expect(screen.getByText('420 x 420 px')).toBeTruthy();
+    const sizeBadge = screen.getByText('420 x 420 px');
+    expect(sizeBadge.className).toContain('rounded-full');
+    expect(sizeBadge.className).toContain('image-canvas-editor__size-badge');
 
     fireEvent.pointerDown(canvasImage.closest('button')!, {
       button: 0,