perf: reduce ESM bundle and package size

[ghiscoding]

Summary

• Optimize the ESM-only build for ES2022 and improve tree shaking
• Reduce published package size by limiting packaged files
• Remove embedded source content from JavaScript source maps while preserving declaration maps and source resolution
• Add gzip and Brotli bundle-size budgets enforced in CI
• Harden the HTML sanitizer fallback against unsafe output
• Preserve virtual-scroll behavior and add regression coverage
• Simplify DOM utilities and avoid redundant layout measurements
• Remove unnecessary Vite demo configuration

Size impact

• JavaScript: 47,702 → 46,697 bytes
• JavaScript gzip: 13,283 → 13,039 bytes
• JavaScript Brotli: 11,959 → 11,762 bytes
• npm package: 122,952 → 93,031 bytes (~24% smaller)
• npm unpacked size: 556,002 → 417,174 bytes (~25% smaller)
• Tree-shaken utility import: 1,911 → 73 minified bytes

Validation

• Full Playwright suite: 92/92 passed
• Security tests passed
• Bundle-size checks passed
• Library and demo builds passed
• TypeScript checks passed
• Biome formatting and lint checks passed
• JavaScript and declaration source-map paths verified

LLM

Implementation and review assisted by GPT-5.6 Sol.

[github-actions]

🎉 This pull request is included in version 5.2.2 📦
🔗 The release notes are available at: GitHub Release 🚀