Refine trends and debug harness; clean up warnings

FuelBoard/StationsView.swift

@@ -44,7 +44,7 @@ struct StationsView: View {
         } else {
             ratio = "\(totalCount)"
         }
-        if let location {
+        if location != nil {
             if sortMode == .closest {
                 return "\(mode) \(fuel) stations — nearest first, best value within \(miles) \(unit) · \(ratio) stations updated"
             }
@@ -174,11 +174,13 @@ struct StationsView: View {
             .navigationTitle("FuelBoard")
             .navigationBarTitleDisplayMode(.large)
             .onAppear {
+#if DEBUG
                 // QA hook: launch with `-showKeySheet` to verify the legend
                 // sheet without driving a tap (simctl has no tap command).
                 if ProcessInfo.processInfo.arguments.contains("-showKeySheet") {
                     showKey = true
                 }
+#endif
             }
             .toolbar {
                 ToolbarItem(placement: .topBarTrailing) {