notify() shows an in-page toast while the window is focused and only
falls back to an OS notification otherwise, but both message and invite
notifications were gated on Notification.permission === granted. Anyone
who declined (or was never asked) heard the ping with nothing on screen.
Gate only the OS path on the permission.
Fixes#324
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5