docs(expenses): add Tricount accommodation ledger

README.md

@@ -5,6 +5,7 @@ Group trip: SF → Yosemite → Sequoia → LA → Las Vegas → SF.
 ## Structure
 
 - [`itinerary.md`](itinerary.md) — full plan: timeline, day-by-day, bookings overview
+- [`expenses.md`](expenses.md) — shared-expense ledger and reconciliation notes
 - [`bookings/`](bookings/) — one file per accommodation / transport booking, with confirmation PDFs
 - [`emails/`](emails/) — host messages and receipts
 - Sights menus — candidate things to see per leg: