Expand watch app backlog

BACKLOG.md

@@ -155,8 +155,20 @@ Status: TODO / IN PROGRESS / DONE / BLOCKED.
   multiple drops from one refresh into a single summary notification rather
   than one alert per station.
 - [ ] **Share sheet** — share "Cheapest Unleaded near me" as text/image card.
-- [ ] **Watch app** — glanceable cheapest-price complication (WatchKit + shared
-  app-group store; watch target would need to be added to the project).
+- [ ] **Watch app v1 — favourites + Check now** — small Apple Watch companion,
+  not a phone-app clone. Favourites-first home screen: fuel picker, `Cheapest
+  favourite` summary card, top few favourites for that fuel, last-updated time,
+  and a prominent `Check now` action that forces a refresh + re-evaluates
+  favourite prices. Keep the watch UX pull-based and glanceable; avoid implying
+  high-frequency background refresh. Shared-store architecture preferred over a
+  second watch-only data model.
+- [ ] **Watch complications / Smart Stack** — complication/widget surfaces for
+  the same watch concept: show the cheapest favourite price, fuel, and short
+  station name at a glance. Keep copy minimal and honest about freshness.
+- [ ] **Watch app v2 — favourite detail + handoff** — tap a favourite row for a
+  detail screen (station, brand, price, last updated) with actions like
+  `Directions` and `Open on iPhone`. Reuse existing maps handoff patterns where
+  possible instead of inventing watch-only navigation logic.
 - [ ] **App Clip** — 10 MB budget for "find cheapest fuel nearby" without install.
 - [ ] **Widget picker: dual-unit distance labels** — the Edit-Widget Distance row
   label is cached by the system at sheet-render time and only re-resolves on