Fetch full-UK dump (no radius/limit); stations in app-group defaults only; alert path keeps focused radius fetch

Shared/FuelStore.swift

@@ -147,15 +147,19 @@ struct FuelStore {
     static let lastRefreshKey = "fuelboard.lastRefresh"      // TimeInterval (seconds since 1970)
 
     // MARK: Stations
+    // The full-UK dataset (~2.9 MB) lives in app-group UserDefaults only —
+    // keychain is for small values and cannot hold it. Read order is
+    // defaults-first for stations (keychain may hold a legacy small set from
+    // older builds; the full country dump always wins).
 
     static func loadStations() -> [FuelStation] {
-        if let data = keychainData(service: stationsKey),
+        if let defaults = UserDefaults(suiteName: appGroupSuite),
+           let data = defaults.data(forKey: stationsKey),
            let stations = try? JSONDecoder().decode([FuelStation].self, from: data),
            !stations.isEmpty {
             return stations
         }
-        if let defaults = UserDefaults(suiteName: appGroupSuite),
-           let data = defaults.data(forKey: stationsKey),
+        if let data = keychainData(service: stationsKey),
            let stations = try? JSONDecoder().decode([FuelStation].self, from: data),
            !stations.isEmpty {
             return stations
@@ -166,7 +170,7 @@ struct FuelStore {
     static func saveStations(_ stations: [FuelStation]) {
         if let data = try? JSONEncoder().encode(stations) {
             UserDefaults(suiteName: appGroupSuite)?.set(data, forKey: stationsKey)
-            writeKeychain(data: data, service: stationsKey)
+            // Intentionally NOT written to keychain — 2.9 MB exceeds its limits.
         }
     }