merge: bring Horseshoe Las Vegas booking from gh/master

Resolve against the bookings/{stays,transport} layout, couple payer
names, and the days/ timeline: move hotel-vegas-horseshoe.md into
bookings/stays/, swap the Wyndham ledger row for Horseshoe US$1,067.70
(KTVT, shared 50/50; settlement now US$715.37), and point Sep 30–Oct 3
day files at the Horseshoe.

Claude-Session: https://claude.ai/code/session_01SQPbfX7jyTALGYxJw36hbT

days/2026-09-30.md

@@ -1,6 +1,6 @@
 # Sep 30 (Wed) — Los Angeles → Las Vegas
 
-**Stay:** [Wyndham Desert Rose](../bookings/stays/wyndham-desert-rose-las-vegas.md) · check-in from 4 PM
+**Stay:** [Horseshoe](../bookings/stays/hotel-vegas-horseshoe.md) · check-in from 4 PM
 
 ## Logistics