- Add returns_result.md documenting Result正規化 (returns_result = true)
- Add when-pattern-matching.md with future pattern matching syntax design
- Update E2E tests to use get_value() for HTTP responses
- Update plugin system README with B案 (Result-based) support
- Remove singleton from HttpServerBox and SocketServerBox for stability
This prepares for gradual migration to Result-based error handling,
starting with Net plugin methods, as agreed with ChatGPT5's design.
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
