v0.4.9 — X,Y coordinates, no-switching can still clear the mainline, Q3 corrected, a clearance bug, three sounds, and the box art

A playtest review of seed 58228926 (day 6), plus one long-standing display complaint and the
first real audio beyond a placeholder.

- Coordinate labels read X,Y everywhere shown to a player, not the internal Y,X storage order.
  Display-only.
- "No switching" now means may not add or drop cars, not "never touch it" — these trains can
  still be moved onto Secondary Track to clear the mainline.
- Q3 corrected: Expedite governs WHERE a train may be left standing, not WHEN it leaves. The
  forced same-Stage departure is gone; a new fault costs 1 Revenue if an expedited train is left
  off the station when a Mainline Phase begins. Resolves "3/4 Express prints a rule it can never
  use" as a side effect.
- evaluateClearance now checks every occupant on a Mainline card before offering a judgment
  call, instead of returning on whichever it found first — found while explaining a playtest
  report, fixed with a regression test.
- Three new synthesised sounds: arrive, depart, crash.
- The splash page shows the box art.

Full detail, measurements and reasoning in CHANGELOG.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FvU99NEakShRMg3nN3fHAZ

package.json

@@ -1,6 +1,6 @@
 {
   "name": "station-master",
-  "version": "0.4.8",
+  "version": "0.4.9",
   "private": true,
   "type": "module",
   "description": "Station Master — a railroad operations game",