docs: update README with testing and compatibility notes

[eajr]

Summary by CodeRabbit

• Documentation
  • Added testing section with CI behavior guidance
  • Updated public API reference
  • Added lifecycle hook compatibility notes across Elysia versions and adapters

[coderabbitai]

Caution

Review failed

The pull request is closed.

📝 Walkthrough

Walkthrough

Documentation updates to README.md including a Testing section with bun test instructions, renaming of the Options interface to IOptions in the public API reference, and compatibility notes for onAfterResponse and onResponse lifecycle hooks.

Changes

Cohort / File(s)	Summary
Documentation README.md	Added Testing section with bun test instructions. Updated public API reference to rename export interface Options to export interface IOptions. Added compatibility documentation for onAfterResponse and onResponse lifecycle hooks across Elysia versions and adapters.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A README grows with wisdom new,
Interface names now crystal-clear in view,
Testing paths and hooks aligned,
Documentation refined, purpose defined! ✨

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch codex/docs-readme-updates

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