v0.7.1 — a caboose is not a load, a Day that says it ended, and a train you may throw away

Four issues off the Gitea tracker, all of them things a player saw at the board. Reasoning for
every item, and what was verified how: CHANGELOG.md.

- Gitea#8: X22 Pee-Dee refused every caboose, including the one it was made up with, so setting it
  out stranded the train. All six cabooses are minted loaded because §2.2's "coloured is loaded,
  white is empty" doubles as a piece count in the supply table; one read of the flag took that
  literally. A caboose carries the crew, not freight, so it is never a load.
- Gitea#10: a Day turns over inside the phases that run themselves, so it passes between one click
  and the next — and both transient signals fade before a player reading the board notices. A modal
  stops and waits, carrying the standings, the Days left and the combined target. Suppressed on the
  first frame, on Undo stepping back across a rollover, and on the Day the game ends.
- Gitea#9, which SUPERSEDES Gitea#6 from three days ago: a Timetabled train may be tossed face-up
  to a Department slot, where a rival may pick it up — the second half of the ruling needed no code,
  since that is where every discard already goes. An Extra still may not. A New Game setting on this
  line (discardTimetabled, on by default), the plain rule on the 0.4.9 line.
- Gitea#2 is not an engine bug: the rules are implemented exactly, and running the coach pool dry is
  Jesse's ruling to keep — "part of the strategy". What was wrong is that the game said nothing. A
  blocked platform now gives its reason, from the engine's own predicate, including how many coaches
  are stranded in Classification and what brings them back.

The same four ship as v0.4.9g on the playtest line.

Closes #2
Closes #8
Closes #9
Closes #10

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FLnYR4XtXQNamYJXGYT8oC

test/train-rules.test.ts

@@ -74,6 +74,8 @@ const west = (s: GameState, n = 2): GridCoord => {
 };
 
 const boxcar = (loaded = false): RollingStock => ({ type: 'boxcar', loaded });
+/** As `ROLLING_STOCK_SUPPLY` mints them: there is no empty caboose in the game. */
+const caboose = (): RollingStock => ({ type: 'caboose', loaded: true });
 const coach = (loaded = false): RollingStock => ({ type: 'coach', loaded });
 
 // ---------------------------------------------------------------------------
@@ -141,6 +143,23 @@ describe('§7 — what a train may couple', () => {
       'EMPTIES_ONLY',
     );
   });
+
+  it('X22 Pee-Dee may still couple a caboose, which is not a load (Gitea#8)', () => {
+    // Every caboose in the game is minted `loaded: true` because the supply table's loaded/empty
+    // split doubles as a piece count. Taken literally that left the per-diem train unable to pick
+    // up ANY caboose, its own included: set it out at the end of a sweep and it was stranded there.
+    const s = game();
+    switching(s, 22, true, [], [caboose()]);
+    assert.equal(check(s, 0, { type: 'switch.move', trayId: 't', to: west(s), reverse: false }), null);
+
+    // The restriction itself is untouched — a loaded car alongside the caboose still refuses.
+    const withLoad = game();
+    switching(withLoad, 22, true, [], [caboose(), boxcar(true)]);
+    assert.equal(
+      check(withLoad, 0, { type: 'switch.move', trayId: 't', to: west(withLoad), reverse: false }),
+      'EMPTIES_ONLY',
+    );
+  });
 });
 
 describe('§7 — one freight car per location (trains 3/4)', () => {