feat: support video cell first frame snapshot

[fangsmile]

Summary

• Based on feat: support video cell first frame snapshot #5206 / Semlaw branch feat-video-poster-render-0706.
• Supports rendering video cells from a first-frame canvas snapshot and releasing video resources after loading.
• Adds the missing Rush changefile for @visactor/vtable.

Verification

• JSON parse check for common/changes/@visactor/vtable/feat-video-first-frame-snapshot_2026-07-06-15-35.json.
• Jest: ./node_modules/.bin/jest tests/cell-type/video-cell-first-frame.test.ts --runInBand --silent=false.
• TypeScript: ./node_modules/.bin/tsc --noEmit --pretty false.

Supersedes #5206.