watch: fix snapshot sync and polish favourites UX

FuelBoard/WatchSyncManager.swift

@@ -46,9 +46,11 @@ final class WatchSyncManager: NSObject, WCSessionDelegate {
         if let favourites = try? JSONEncoder().encode(FuelStore.loadFavourites()) {
             context[FuelStore.favouritesKey] = favourites
         }
-        if let stations = try? JSONEncoder().encode(FuelStore.loadStations()) {
-            context[FuelStore.stationsKey] = stations
-        }
+        // Do NOT send the full station dump to watchOS via WatchConnectivity.
+        // The UK dataset is megabytes large and exceeds application-context
+        // payload limits, which prevents any snapshot from arriving. The
+        // favourites payload already carries station snapshots + prices, so the
+        // watch can render favourites without the full list.
 
         context[FuelStore.fuelKey] = FuelStore.loadSelectedFuel().rawValue
         context[FuelStore.distanceUnitKey] = FuelStore.loadDistanceUnit().rawValue