- Remove internal development docs (phase tracking, implementation plans, security audits)
- Move DEVELOPMENT.md to docs/contributing/ for contributor guidance
- Move TROUBLESHOOTING.md from root to docs/ folder
- Add docs/INDEX.md as navigation hub for all documentation
- Clean up docs to focus on user/self-hoster facing content
This reorganization separates user-facing documentation from
internal contributor documentation, making the project more
approachable for self-hosters.