Real iPhone wallpaper + populated Favourites captures

- PreviewWallpaper image set: the actual iPhone wallpaper extracted from the
  iOS 26.3 sim runtime (ActionButtonSelector Display.ca, 1320x2870 native
  res, JPEG ~180 KB) — replaces the gradient backdrop in the widget mock
- -seedFavourite <substring> launch hook: pins the first matching station
  for Unleaded via the normal keychain+app-group save path, so the
  Favourites tab can be captured populated (Ring Road Service Station,
  129.9, 59.1 mi, TOP badge)
- Re-captured 2-favourites (light), 6-favourites-dark, 9-widgets-dark,
  10-widgets-light with real data
- 95/95 tests green; Release IPA rebuilt + re-served

FuelBoard/WidgetMockScreen.swift

@@ -6,11 +6,13 @@ import WidgetKit
 /// code the widget extension renders) at small + medium sizes. Used for App
 /// Store screenshot captures; not reachable from the UI.
 struct WidgetMockScreen: View {
-    @Environment(\.colorScheme) private var colorScheme
-
     var body: some View {
         ZStack {
-            wallpaper
+            // Real iPhone wallpaper (extracted from the iOS 26.3 sim runtime —
+            // ActionButtonSelector Display.ca asset, 1320×2870 native res).
+            Image("PreviewWallpaper")
+                .resizable()
+                .scaledToFill()
                 .ignoresSafeArea()
 
             VStack(alignment: .leading, spacing: 26) {
@@ -23,10 +25,12 @@ struct WidgetMockScreen: View {
                     VStack(alignment: .leading, spacing: 3) {
                         Text("FuelBoard")
                             .font(.title2.bold())
-                            .foregroundStyle(.primary)
+                            .foregroundStyle(.white)
+                            .shadow(radius: 2, y: 1)
                         Text("Cheapest fuel near you")
                             .font(.subheadline)
-                            .foregroundStyle(.secondary)
+                            .foregroundStyle(.white.opacity(0.9))
+                            .shadow(radius: 2, y: 1)
                     }
                 }
                 .padding(.top, 8)
@@ -40,32 +44,6 @@ struct WidgetMockScreen: View {
         }
     }
 
-    /// iOS-default-style wallpaper (dark navy → black in dark mode, soft
-    /// blue-grey in light), matching the system default look.
-    private var wallpaper: some View {
-        Group {
-            if colorScheme == .dark {
-                LinearGradient(
-                    colors: [
-                        Color(red: 0.09, green: 0.14, blue: 0.26),
-                        Color(red: 0.05, green: 0.08, blue: 0.15),
-                        Color(red: 0.02, green: 0.03, blue: 0.06)
-                    ],
-                    startPoint: .topLeading, endPoint: .bottomTrailing
-                )
-            } else {
-                LinearGradient(
-                    colors: [
-                        Color(red: 0.72, green: 0.80, blue: 0.94),
-                        Color(red: 0.85, green: 0.90, blue: 0.97),
-                        Color(red: 0.94, green: 0.96, blue: 0.99)
-                    ],
-                    startPoint: .topLeading, endPoint: .bottomTrailing
-                )
-            }
-        }
-    }
-
     private func widgetCard(_ family: WidgetFamily, label: String) -> some View {
         // Real widget proportions: system small content is 158×158pt,
         // medium 338×158pt (card adds the 14pt padding each side).