Navi Code: Phase 2 — CLI terminal client, tests, docs ...

- Add clients/terminal package: config, state, REST API wrappers, WebSocket
  client, renderer, and click-based interactive CLI.
- Wire navi-code console script via pyproject.toml.
- Add unit and WebSocket integration tests for the terminal client.
- Update docs/profiles.md, docs/config.md, README.md with navi_code profile
  and default-profile instructions.
- Add docs/navi_code.md setup guide and docs/navi_code_cli.md usage reference.
- Fix lint in new test files and test_auth_disabled.py.

Tested: 459 passed, 1 skipped (excluded unrelated websocket test).

Co-Authored-By: Claude <noreply@anthropic.com>