Live Activity: own fuel + distance config, independent of Stations tab

- Settings → Live Activity now has Fuel and Distance pickers (5/10/15,
  unit-aware) stored under fuelboard.liveActivityFuel / liveActivityRadiusMiles
- LiveActivityManager uses these instead of the Stations-tab selectedFuel /
  stationLimit; Stations changes no longer re-target the pill
- Fuel moved from Activity attributes into ContentState so changing fuel in
  Settings updates the RUNNING activity in place (no end+restart needed)
- Stations tab stays a pure data-interrogation + favourites surface

FuelBoard/ContentView.swift

@@ -15,6 +15,8 @@ struct ContentView: View {
     @State private var alertsRadius: Double = FuelStore.loadAlertsRadius()
     @State private var alertsFuel: FuelType = FuelStore.loadAlertsFuel()
     @State private var liveActivityEnabled: Bool = FuelStore.loadLiveActivityEnabled()
+    @State private var liveActivityFuel: FuelType = FuelStore.loadLiveActivityFuel()
+    @State private var liveActivityRadiusMiles: Int = FuelStore.loadLiveActivityRadiusMiles()
     @State private var location: Coordinate? = {
         if let loc = FuelStore.loadLocation() { return Coordinate(lat: loc.lat, lng: loc.lng) }
         return nil
@@ -251,7 +253,6 @@ struct ContentView: View {
         .onChange(of: selectedFuel) { _, _ in
             // No re-fetch needed — one response carries E5/E10/DIESEL prices.
             WidgetCenter.shared.reloadAllTimelines()
-            updateLiveActivity()
         }
         .onChange(of: stationLimit) { _, newValue in
             // Distance filter is LOCAL math now — the cache holds the full-UK
@@ -260,7 +261,6 @@ struct ContentView: View {
             // next render.
             FuelStore.saveStationLimit(newValue)
             WidgetCenter.shared.reloadAllTimelines()
-            updateLiveActivity()
         }
         .onChange(of: alertsEnabled) { _, newValue in
             FuelStore.saveAlertsEnabled(newValue)
@@ -289,6 +289,16 @@ struct ContentView: View {
             FuelStore.saveLiveActivityEnabled(newValue)
             updateLiveActivity()
         }
+        .onChange(of: liveActivityFuel) { _, newValue in
+            // The pill tracks its OWN fuel — independent of the Stations tab.
+            FuelStore.saveLiveActivityFuel(newValue)
+            updateLiveActivity()
+        }
+        .onChange(of: liveActivityRadiusMiles) { _, newValue in
+            // Same for its own radius (miles, converted at use).
+            FuelStore.saveLiveActivityRadiusMiles(newValue)
+            updateLiveActivity()
+        }
         .onChange(of: distanceUnit) { _, _ in
             // Distance unit changes the radius — mirror the new radius in the
             // Live Activity immediately.
@@ -298,13 +308,13 @@ struct ContentView: View {
 
     /// Pushes the current best-in-radius station into the Live Activity.
     /// No-op (or ends the activity) when the toggle is off or there's no
-    /// location/data yet. Mirrors the app list's TOP badge: selected fuel +
-    /// chosen distance radius, cheapest then nearest on ties.
+    /// location/data yet. Uses the Live Activity's OWN fuel + radius (set in
+    /// Settings) — independent of the Stations-tab fuel/distance.
     private func updateLiveActivity() {
         LiveActivityManager.update(
             stations: stations,
-            fuel: selectedFuel,
-            radiusKM: distanceUnit.toKM(Double(stationLimit)),
+            fuel: liveActivityFuel,
+            radiusKM: distanceUnit.toKM(Double(liveActivityRadiusMiles)),
             location: location,
             enabled: liveActivityEnabled
         )
@@ -316,6 +326,8 @@ struct ContentView: View {
         SettingsView(
             distanceUnit: $distanceUnit,
             liveActivityEnabled: $liveActivityEnabled,
+            liveActivityFuel: $liveActivityFuel,
+            liveActivityRadiusMiles: $liveActivityRadiusMiles,
             alertsFuel: alertsFuel,
             alertsRadiusKM: alertsRadius,
             testAlertResult: monitor.lastTestResult,