Fix Release archive build for Best Value diagnostics; bump build to 26

FuelBoard/ContentView.swift

@@ -347,8 +347,12 @@ struct ContentView: View {
         return ordered
     }
 
-    #if DEBUG
+    /// Compiled in EVERY configuration: the detail sheet's `journeyDiagnostics`
+    /// argument is not conditional (an `#if` inside an argument list does not
+    /// build), so this symbol must exist for Release/Archive too. Only the panel
+    /// that renders it is `#if DEBUG`; Release returns nil and does no work.
     private func journeyDiagnostics(for station: FuelStation, baseline: FuelStation?) -> FuelSavingsJourneyDiagnostics? {
+        #if DEBUG
         guard let location else { return nil }
         let stationDistance = FuelStore.roadDistanceDiagnostics(for: station, userLat: location.lat, userLng: location.lng)
         let baselineDiagnostics = baseline.map { FuelStore.roadDistanceDiagnostics(for: $0, userLat: location.lat, userLng: location.lng) }
@@ -397,8 +401,12 @@ struct ContentView: View {
             ("Net saving", result.map { FuelSavingsFormat.money($0.netSavingGBP) } ?? "—")
         ]
         return FuelSavingsJourneyDiagnostics(rows: rows)
+        #else
+        return nil
+        #endif
     }
 
+    #if DEBUG
     /// Last FB-DRIVE line printed, so the ranking (which runs on every render)
     /// only reports when the result actually changes.
     private static var lastDriveLogLine: String?