bookings: add Water for Elephants tickets, Sep 27

Ticketmaster order 57-46264/LA2: 4 seats at the Hollywood Pantages,
US$230.00 paid by KTVT, shared 50/50. Rework the Sep 27 plan around
the 6:30 PM show and update the settlement.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

@@ -10,6 +10,7 @@ Group trip: SF → Yosemite → Sequoia → LA → Las Vegas → SF.
 - [`expenses.md`](expenses.md) — shared-expense ledger and reconciliation notes
 - [`bookings/stays/`](bookings/stays/) — one Markdown summary per accommodation booking
 - [`bookings/transport/`](bookings/transport/) — one Markdown summary per flight or car booking
+- [`bookings/activities/`](bookings/activities/) — one Markdown summary per ticketed activity or show
 - [`sources/stays/`](sources/stays/) — original accommodation confirmations, messages, and receipts (`.pdf` / `.eml`)
 - [`sources/transport/`](sources/transport/) — original transport confirmations and tickets (`.pdf` / `.eml`)
 - Add matching `bookings/<category>/` and `sources/<category>/` directories if another booking type occurs (for example, `activities`)