Cache-first refresh policy: auto-fetch at most twice a day (12h gate), no fetch on launch/foreground/location/fuel-switch, pull-to-refresh forces; geofences still follow location

FuelBoard/ContentView.swift

@@ -87,7 +87,8 @@ struct ContentView: View {
                 location: location,
                 radiusKM: alertsRadius,
                 favouriteIDs: favouriteIDs,
-                onToggleFavourite: toggleFavourite
+                onToggleFavourite: toggleFavourite,
+                onRefresh: { await refresh(force: true) }
             )
             .tabItem { Label("Stations", systemImage: "fuelpump.fill") }
 
@@ -113,6 +114,7 @@ struct ContentView: View {
             monitor.update(stations: stations, favourites: refreshedFavourites,
                            fuel: selectedFuel, radiusKM: alertsRadius)
             monitor.setEnabled(alertsEnabled)
+            // Refresh only when the cache is stale (twice-a-day policy).
             Task { await refresh() }
         }
         .onChange(of: scenePhase) { _, newPhase in
@@ -120,7 +122,7 @@ struct ContentView: View {
                 locationManager.startForegroundTracking()
                 monitor.update(stations: stations, favourites: refreshedFavourites,
                                fuel: selectedFuel, radiusKM: alertsRadius)
-                Task { await refresh() }
+                // No network fetch on foreground — pull-to-refresh is the override.
             } else {
                 locationManager.stopForegroundTracking()
             }
@@ -130,13 +132,15 @@ struct ContentView: View {
                 location = newLocation
                 FuelStore.saveLocation(lat: newLocation.lat, lng: newLocation.lng)
                 WidgetCenter.shared.reloadAllTimelines()
-                Task { await refresh() }
+                // Geofences follow the user's position, but the station list is
+                // NOT re-fetched on every movement (cached, twice-a-day policy).
+                monitor.update(stations: stations, favourites: refreshedFavourites,
+                               fuel: selectedFuel, radiusKM: alertsRadius)
             }
         }
         .onChange(of: selectedFuel) { _, _ in
-            // Re-fetch so the station set matches the selected fuel (relay
-            // filters by grade); all prices still come back in one response.
-            Task { await refresh() }
+            // No re-fetch needed — one response carries E5/E10/DIESEL prices.
+            WidgetCenter.shared.reloadAllTimelines()
         }
         .onChange(of: alertsEnabled) { _, newValue in
             FuelStore.saveAlertsEnabled(newValue)
@@ -166,13 +170,19 @@ struct ContentView: View {
                        fuel: selectedFuel, radiusKM: alertsRadius)
     }
 
-    private func refresh() async {
+    /// Fetches fresh prices, but only when the cache is stale — unless
+    /// `force` is true (pull-to-refresh is the manual override).
+    private func refresh(force: Bool = false) async {
+        if !force, FuelStore.isCacheFresh {
+            return  // data already fresh — skip network entirely
+        }
         isLoading = true
         defer { isLoading = false }
         do {
             let fetched = try await FuelPriceProvider.active.fetchStations(near: location?.lat, lng: location?.lng, fuel: selectedFuel)
             stations = fetched
             FuelStore.saveStations(fetched)
+            FuelStore.saveLastRefresh()
             WidgetCenter.shared.reloadAllTimelines()
             statusMessage = "Loaded \(fetched.count) stations · \(Date().formatted(date: .omitted, time: .shortened))"
         } catch {