Add crew/player/rat name to page title

Each routed page now sets a descriptive document.title so tabs and
browser history entries are distinguishable: the dashboard shows the
Pi-Rat (and human player) name plus crew, the admin panel shows
"Admin · {crew}", the join page is labeled, and home resets to the
app name. New lib/title.js helper composes "{parts} — Rats with Gats".

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

TODO.md

@@ -5,7 +5,6 @@
 
 ## Minor Gameplay Polish
 
-- [ ] **Add crew/player/rat name to page title, if available**. This will make it easier to distinguish tabs/browser history entries
 - [ ] **Save active sessions in browser local storage**. Whenever you create or join a game, your browser local storage should be updated with the game ID, player ID, crew name, and player/rat names (if available). Going to the home page with saved sessions should provide a menu of games to rejoin in addition to the ability to start a new game. It should be possible to delete entries from this list, which only affects the browser local storage, not the backend database, and is undoable (the entry doesn't disappear immediately, it's just marked as deleted until page refresh).
 - [ ] **Dead Pi-Rat rank voting streamlined**. Don't allow voting for dead Pi-Rats. If a player's only vote options are dead, then they skip voting entirely.