Add XDG-compliant config storage and profile-based auth to okarakeep
Modernize the CLI to use proper config management:
- Store credentials in ~/.config/karakeep/profiles/<name>/credentials.toml
- Add auth commands: login, logout, status, profile list/switch/current
- Support multiple profiles for different Karakeep instances
- Maintain backward compatibility with legacy .karakeep-api file and env vars
New modules: karakeep_config (TOML config storage), karakeep_auth_cmd (auth CLI)
Dependencies: xdge, tomlt
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>