All fuel prices per station (E10/E5/Diesel from one fetch); re-fetch on fuel switch; fuel tabs populate instantly

FuelBoard/ContentView.swift

@@ -120,6 +120,11 @@ struct ContentView: View {
                 Task { await refresh() }
             }
         }
+        .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() }
+        }
         .onChange(of: alertsEnabled) { _, newValue in
             FuelStore.saveAlertsEnabled(newValue)
             monitor.setEnabled(newValue)

Shared/FuelPriceProvider.swift

@@ -56,7 +56,7 @@ struct RelayFuelProvider: FuelPriceProviding {
                 postcode: relay.postcode ?? "",
                 lat: relay.lat ?? 0,
                 lng: relay.lng ?? 0,
-                prices: [fuel: relay.price],
+                prices: relay.allPrices,
                 priceUpdated: nil
             )
         }
@@ -72,7 +72,29 @@ private struct RelayResponse: Codable {
         let postcode: String?
         let lat: Double?
         let lng: Double?
-        let price: Double
+        let price: Double?
+        let prices: [String: Double]?
+
+        /// Map relay grade keys (E5/E10/DIESEL) to FuelType for ALL fuels the
+        /// station sells — one fetch populates every fuel tab.
+        var allPrices: [FuelType: Double] {
+            var result: [FuelType: Double] = [:]
+            if let prices {
+                for (grade, value) in prices {
+                    switch grade.uppercased() {
+                    case "E10": result[.e10] = value
+                    case "E5": result[.e5] = value
+                    case "DIESEL", "B7", "B7S", "B7P", "B10": result[.diesel] = value
+                    default: break
+                    }
+                }
+            }
+            // Backwards-compat: relay versions without `prices` still send `price`.
+            if result.isEmpty, let price {
+                result[.e10] = price
+            }
+            return result
+        }
     }
     let stations: [RelayStation]
 }