0.7.1:0 — bundle Station Master v0.7.1

Four playtest fixes off the Gitea tracker. The submodule pin moves to v0.7.1 and the version follows
it; the downstream digit resets to :0, since v0.7.0 only ended on :3 because three test packs were
played before it was released.

- An empties-only train may couple a caboose again — a caboose carries the crew, not freight.
- The end of a Day is a modal carrying the standings, the Days left and the combined target, instead
  of passing between one click and the next inside the automatic phases.
- A Timetabled train may be discarded to a Department pile for a rival to pick up, governed by a new
  discardTimetabled setting that appears in both the New Game dialog and the lobby, on by default. An
  Extra never may.
- A blocked passenger platform now gives its reason, including the coach shortage and what ends it.

No new version file and no migration: current.ts's migrations.up is empty and nothing is carried from
0.7.0. GAMES IN PROGRESS SURVIVE THIS UPDATE — all three engine-visible changes only widen what is
legal, so every intent a 0.7.0 game recorded still replays, and the server resumes a save by replaying
it rather than by comparing version strings (src/server/index.ts in the game repo).

README.md and instructions.md both named 0.7.0 and carry the three user-visible changes now.

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

instructions.md

@@ -43,6 +43,18 @@ changing any of them marks the game **Custom**, which keeps the scoring of the t
 from. The seed, the number of players and the number of Days sit above the type and do not make a
 game Custom — the targets re-derive from them.
 
+**What changed in 0.7.1.** Three things you will see at the table. The **end of a Day now stops and
+says so** — a dialog with the standings, how many Days are left and the combined target, because a
+Day used to turn over inside the phases that run themselves and pass between one click and the next.
+A **Timetabled train may now be thrown away**: toss it face-up to a Department slot and a rival may
+pick it up. That is a New Game setting (*A Timetabled train may be discarded*, on by default) — turn
+it off and a train card can only ever be played onto the timetable. An **Extra is never discardable**
+either way. And a **platform where nothing can be worked now tells you why** — no train for the
+passengers waiting, a train whose card bars Porters, coaches already full, the same-district rule, or
+the Division Yard being out of coaches, in which case it says how many are stranded in the
+Classification Yard and what brings them back. Running out of coaches is part of the game, not a
+fault; what was missing was the explanation.
+
 **Leaving, and coming back.** Anyone may leave a lobby, and the host can clear a chair, so a
 mis-join or somebody who wanders off no longer blocks a table that cannot start until every seat is
 taken. A **Leave game** button appears once a game is running: it keeps your seat and the table