itinerary: split day plans into days/, plan SF Sep 21

- One file per day under days/; timeline table reduced to date, weekday, place
- Sep 19–20: KT & VT Uber to Airbnb, rest day; LK & MS drive rental to Airbnb
- Sep 21: Silicon Valley morning, optional Twin Peaks / Painted Ladies /
  Lands End, Battery Spencer at sunset
- LK Hertz LAX rental marked not available for planning; LA / San Diego
  hotels cancelled
- sf_sights: add Silicon Valley and Mission / Castro, skip Computer History
  Museum

Claude-Session: https://claude.ai/code/session_01CWLR7htYGAB9i89P8jCCLn

days/2026-09-20.md

@@ -0,0 +1,14 @@
+# Sep 20 (Sun) — San Francisco — LK & MS arrive
+
+**Stay:** [Airbnb — Daly City](../bookings/stays/airbnb-sf-daly-city.md)
+
+## Logistics
+
+- LK & MS: UA1333 lands SFO **12:11 PM** ([flights](../bookings/transport/flights-ms.md)) → [SIXT rental](../bookings/transport/car-rental.md) pickup **1:00 PM** → drive to the Airbnb (parking included — ask host for details)
+- KT & VT: BART from Daly City in the morning, meet up after the pickup
+
+## Plan
+
+> Menu: [`sf_sights.md`](../sf_sights.md). Items below are agreed; everything else is still on the menu.
+
+- TBD