Adds a "🚪 Leave Game" option to the corner menu for every player, so someone
who's done can remove themselves instead of waiting for an admin to kick them.
leave_game reuses the kick mechanics (cards to discard, reference cleanup,
phase re-check) via a shared _remove_player helper; it logs a friendlier
"left the crew" event and, like kick, refuses the last Admin so the table
isn't orphaned. The self-service route POST /game/{gid}/player/{pid}/leave
lives next to join and authenticates on the player's own id (no admin key).
The handler confirms, forgets the saved session, and routes home.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Tim McCarthy
e7db19f27e