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

src/engine/content.ts

@@ -504,8 +504,9 @@ export type MainlineKind =
   | 'uncontrolledSiding' | 'tunnel' | 'trestle' | 'interchange';
 
 /**
- * Speed as printed. `60` and `30` appear on the cards; Hilly prints P60/F30, and Heavy Grade
- * prints "G" with the player setting orientation.
+ * Speed as printed. `60` and `30` appear on the cards; Hilly prints P60/F30, and Heavy Grade prints
+ * "G" — no number at all, plus "Player sets orientation", **which the game deliberately does not do**
+ * (see `gradeReduction` below, and implications.md §10 Q11).
  *
  * WHAT THESE NUMBERS MEAN IS NOT YET SETTLED — see implications.md §10 Q2. Transcribed as data so
  * the answer can be applied without re-reading the cards.
@@ -531,6 +532,14 @@ export const MAINLINE_PROFILES: readonly MainlineProfile[] = [
   { kind: 'plains', name: 'Plains', speed: { kind: 'uniform', value: 60 }, trainsMayPass: false, sortsCars: false, entryPoints: ['start'] },
   { kind: 'curves', name: 'Curves', speed: { kind: 'uniform', value: 30 }, trainsMayPass: false, sortsCars: false, entryPoints: ['start'] },
   { kind: 'hilly', name: 'Hilly', speed: { kind: 'byTrainType', passenger: 60, freight: 30 }, trainsMayPass: false, sortsCars: false, entryPoints: ['passenger', 'freight'] },
+  /**
+   * `entryPoints` is TRANSCRIBED, NOT READ — nothing anywhere reads this field on any profile, and
+   * the printed start positions are not modelled: `crossingStages` counts Stages instead. Recorded
+   * here because implications.md §6 describes the card as having FIVE distinct starts (plain,
+   * brakemen, airbrakes, plain, helpers) against the four listed, and that discrepancy should be
+   * settled against `Mainline Cards.pdf` if the starts are ever implemented — not quietly "fixed"
+   * now, when nothing depends on it either way.
+   */
   { kind: 'heavyGrade', name: 'Heavy Grade', speed: { kind: 'grade' }, trainsMayPass: false, sortsCars: false, entryPoints: ['start', 'brakemen', 'airbrakes', 'helpers'] },
   { kind: 'doubleTrack', name: 'Double Track', speed: { kind: 'uniform', value: 60 }, trainsMayPass: true, sortsCars: false, entryPoints: ['start'] },
   { kind: 'uncontrolledSiding', name: 'Uncontrolled Siding', speed: { kind: 'uniform', value: 60 }, trainsMayPass: true, sortsCars: false, entryPoints: ['noPass', 'passingTrains'] },
@@ -664,12 +673,24 @@ export function mainlineDescription(kind: MainlineKind, gradeUp: Direction = 'ea
 }
 
 /**
- * Q11, answered: the Heavy Grade card prints "(Up)" and "Player sets orientation", so which way it
- * climbs is a property of the placed card, not a constant. `gradeUp` is the direction a train is
- * travelling when it goes UPHILL; a train heading the other way is descending.
+ * WHICH WAY THE GRADE CLIMBS, AND WHY NO PLAYER CHOOSES IT.
+ *
+ * Q11, answered from the card: Heavy Grade prints "(Up)" and "Player sets orientation", so the climb
+ * is a property of the PLACED CARD rather than a compass constant. `gradeUp` is the direction a train
+ * is travelling when it goes UPHILL; a train heading the other way is descending.
+ *
+ * **The second half of that print is deliberately overridden.** No player sets it — `setup.ts` rolls
+ * it from the seed. Settled v0.5.0 and re-confirmed 2026-08-23 after the question was raised again:
+ * a Heavy Grade always sits BETWEEN two districts (or beyond an end Division Point next to one),
+ * never inside one player's own, so there is no player with a fair claim to the choice — and the
+ * choice is not cosmetic, because it decides which of the three modifiers below can ever pay and
+ * therefore which direction of traffic is favoured, permanently. Giving it to the Superintendent was
+ * considered and rejected in that re-examination: the office rotates every three Stages, the
+ * advantage does not. Full reasoning in implications.md §10 Q11.
  *
  * Each applicable card takes a Stage off, never below one: a train cannot cross in no time.
- * Airbrakes only counts when Brakeman is already there, which the placement rule enforces.
+ * Airbrakes only counts when Brakeman is already there, which the placement rule enforces
+ * (`MAINLINE_MODIFIER_RULES`, `requiresOnCard`).
  */
 function gradeReduction(
   profile: MainlineProfile,