[codex] Sync extension marks before hover frames render

[xuefei1313]

What changed

• Move ExtensionMarkSyncStatePlugin state copying from the chart afterRender event to the VRender stage beforeRender hook.
• Keep the chart afterRender subscription only to attach or rebind the stage hook after the stage is available or recreated.
• Clean up both chart-event and stage-hook subscriptions on release or when syncState is no longer detected.

Why

syncState extension marks were copying the primary mark state after the frame had already rendered. For hover-driven outlines this made the outline appear one render late: hovering a bar did not show the outline, while pointerout could show the previous active state.

Copying states in beforeRender ensures extension marks receive the latest primary mark state before the current frame is drawn.

Validation

• User confirmed the local runtime page interaction now behaves correctly.
• Ran git diff --check.
• Attempted rushx compile in packages/vchart-extension; it is currently blocked by existing unrelated @visactor/vchart export/type errors across the package, so it was not a valid signal for this change.

[xuefei1313]

🦞 Aime Bot Review

改动摘要

本 PR 修复了 ExtensionMarkSyncStatePlugin 中 syncState 扩展 mark 的状态同步时机问题。核心改动是将状态同步从 VChart 的 afterRender 事件移至 VRender stage 的 beforeRender hook，确保扩展 mark 在当前帧绘制前就能获取到主 mark 的最新状态，从而修复 hover 轮廓延迟一帧显示的问题。

代码观察与建议

整体设计合理，通过引入 _unsubscribeBeforeRender 和 _subscribedStage 两个私有字段，对 stage hook 的生命周期管理与已有的 event 订阅管理保持了一致的风格，值得肯定。

以下几点供参考：

1. _ensureBeforeRenderSyncHook 中的 try/catch：getStage?.() 已使用可选链，通常不会抛出，但用 try/catch 兜底也无妨。可以考虑仅保留可选链而去掉 try/catch 以减少冗余，当然保留也不影响正确性。

2. onAfterInitChart 中的提前清理：

   if (!this._detectSyncState(chartSpec)) {
     this._unsubscribeAfterRender?.();
     this._unsubscribeBeforeRender?.();
     return;
   }

   这里在无 syncState 时主动取消订阅，逻辑是正确的。请确认是否存在 chart spec 动态变更（先有 syncState 后去除）的场景，若有，这段清理逻辑正好覆盖了该情况，👍。

3. release() 中未清理 _subscribedEvent 和 _subscribedStage：父类 super.release() 是否会处理这些引用？如果不会，建议在 release() 中手动将它们置为 undefined，避免潜在的内存泄漏。

4. 文件末尾 patch 截断：diff 中 _detectSyncState 方法的检测逻辑被截断，从已有代码来看逻辑完整，问题不大。

合并建议

改动目标明确，修复逻辑清晰，代码整洁。建议关注第 3 条关于 release() 后引用清理的问题后，可以合并。感谢贡献！ 🎉