sloproxy

feat(executor): extend `applyClaudeHeaders` and Kimi executor with additional header support master

- Added an `incomingHeaders` argument to `applyClaudeHeaders` to enable external header injection for flexibility. - Updated Kimi executor to delegate header support to Claude executor, facilitating upstream request logging and beta header forwarding. - Introduced tests for delegated configuration, header handling, and upstream request/response logging to improve coverage.