v0.7.0 — four game types, a lobby you can read and leave, and a multiplayer game that makes a sound

The multiplayer set-up, the lobby, the start of a game, and four signals a remote client had never
been sent. Reasoning, the preset table and what was verified how: CHANGELOG.md.

- Co-op, Competitive, Cutthroat, Solitaire and Custom, on both screens, from one shared block —
  they had drifted, and each was missing a question the other asked.
- A player reads the whole rule set before taking a seat, may leave a lobby or a running game, and
  keeps a seat across a reload. The host may clear a chair. The browser remembers every game it is
  in, not just the last one.
- The start of a game is drawn: a handoff beat, an announcement, the code and type in the header.
- Sound, the timetable flash, announcements and the just-drawn badge now reach a remote client;
  justDrawn goes to the seat that drew it and nobody else.
- Played on StartOS, which found the rest: an Extra belongs to the player who played it, the board
  never named the Superintendent, bot seats were reported as absent players, and rule section
  numbers are out of every string a player reads.

Also carries the previous session's Heavy Grade documentation work — asked again, answer unchanged.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016JczK5i33ZNSf2PtzZqdhS

test/advance.test.ts

@@ -1036,7 +1036,8 @@ describe('an Extra starts where the player puts it (Gitea#4)', () => {
    */
   const pending = (trainNumber: number, tier?: 'depot' | 'station'): GameState => {
     const s = game(11);
-    s.pendingExtras = [trainNumber];
+    // Queued by seat 0, who is therefore the one §7 lets place it.
+    s.pendingExtras = [{ trainNumber, player: 0 }];
     s.timetable = s.timetable.map(() => null);
     if (tier) s.officeAreas.get(0)!.tier = tier;
     s.clock.phase = 'newTrain';