[codex] fix duplicated pre-render event listeners

[xuefei1313]

🤔 This is a ...

• New feature
• Bug fix
• TypeScript definition update
• Bundle size optimization
• Performance optimization
• Enhancement feature
• Refactoring
• Update dependency
• Code style optimization
• Test Case
• Branch merge
• Release
• Site / documentation update
• Demo update
• Workflow
• Other (about what?)

🔗 Related issue link

N/A

🔗 Related PR link

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🐞 Bugserver case id

N/A

💡 Background and solution

When a VChart instance is created with an empty initial spec and a user registers a chart/model-level event before calling updateSpec, the type change causes the reMake path to run before any chart/model has been initialized.

The user callback is already registered in the event dispatcher at that point. The old reMake logic always replayed _userEvents, so the same callback was inserted into the event bubble queue twice and one click could trigger the handler twice.

This change only replays _userEvents when a prior chart instance existed and its release path could have cleared dispatcher handlers. It preserves the existing replay behavior for real remakes while avoiding duplicate registration for pre-render/updateSpec initialization.

A regression test covers the reported sequence:

const vc = new VChart({ type: '' }, options);
vc.on('click', { source: 'chart', level: 'model' }, cb);
vc.updateSpecSync(barSpec);

📝 Changelog

Language	Changelog
🇺🇸 English	Fix duplicate chart/model event callbacks when events are registered before updateSpec initializes the chart.
🇨🇳 Chinese	修复在 updateSpec 初始化图表前注册 chart/model 事件时，回调被重复触发的问题。

☑️ Self-Check before Merge

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

---

🚀 Summary

• Added a regression test for pre-updateSpec user event registration.
• Skipped _userEvents replay when reMake runs without a prior chart instance.

🔍 Walkthrough

• packages/vchart/src/core/vchart.ts: gate user event replay on whether a previous chart existed before reMake release.
• packages/vchart/__tests__/unit/core/vchart.test.ts: verify a model-level click callback registered before updateSpecSync only fires once.

✅ Validation

• npm test -- __tests__/unit/core/vchart.test.ts --runInBand
• npm test -- __tests__/unit/event/event.test.ts --runInBand
• npm run compile
• npx eslint src/core/vchart.ts __tests__/unit/core/vchart.test.ts (0 errors; existing warnings)
• pre-push rush test --only tag:package (47 vchart suites / 136 tests passed; existing MaxListenersExceededWarning shown)