[Code Quality] Config parser comment claims YAML upgrade pending; README already documents YAML config

[coderabbitai]

Summary

src/config/manager.ts contains the comment // Simple parser that handles JSON (we'll upgrade to yaml later) and uses JSON for storage, but the README and docs/CONFIGURATION.md describe YAML-based configuration. The two sources of truth are out of sync.

Impact

• Users following the docs may create YAML config files that are silently ignored (JSON.parse will throw)
• Developers are misled about the intended implementation

Recommended Fix

Either:

1. Implement YAML parsing using the js-yaml package (add as dependency) and update the file extension from .json to .yaml
2. Update the documentation to reflect JSON-only config

Backlink: #1