修复序列帧播放淡入闪烁

序列帧图片不再复用普通图片加载淡入样式

补充画布序列帧无过渡播放回归测试

记录序列帧播放闪烁排障经验

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

@@ -1087,6 +1087,14 @@ describe('ImageCanvasWorldView', () => {
     expect(frame.getAttribute('src')).toBe(
       'https://oss.example.com/frame01.png?signature=1',
     );
+    expect(frame.className).toBe(
+      'image-canvas-editor__layer-image-sequence-frame',
+    );
+    expect(frame.style.opacity).toBe('0');
+    expect(frame.style.transition).toBe('none');
+    fireEvent.load(frame);
+    expect(frame.style.opacity).toBe('1');
+    expect(frame.style.transition).toBe('none');
     expect(within(layerButton).getByText('1/2')).toBeTruthy();
     expect(within(layerButton).getByText('动作')).toBeTruthy();
 

src/components/image-editor/ImageCanvasWorldView.tsx

@@ -755,16 +755,14 @@ function ImageCanvasImageSequenceFrame({
       alt={isVisible ? `画布序列帧：${layer.title}` : ''}
       aria-hidden={isVisible ? undefined : true}
       decoding="async"
-      className={`image-canvas-editor__layer-image-sequence-frame ${
-        isVisible && isLoaded
-          ? 'image-canvas-editor__layer-image--loaded'
-          : 'image-canvas-editor__layer-image--loading'
-      }`}
+      className="image-canvas-editor__layer-image-sequence-frame"
       style={{
         inset: 0,
         opacity: isVisible && isLoaded ? 1 : 0,
         position: 'absolute',
+        transition: 'none',
         transform: mediaTransform,
+        zIndex: 1,
       }}
       onLoad={() => onFrameReady(frameKey)}
       onError={() => onFrameReady(frameKey)}