Settings Debug: device coordinates + in-range station indicator

- Debug section now shows the last device fix (lat/lng to 5dp) and its age.
- In-range indicator uses the SAME criteria as live alerts: stations selling
  the monitored fuel within the alert radius of the fix. Green dot + count
  when in range, red when none, grey while waiting for a fix.
- Shows the cheapest in-range station (name, distance, price).
- ProximityMonitor recomputes the snapshot on every location/stations
  change and on Debug-section appear; ContentView passes the live status.
- SettingsView extracted to its own property to keep TabView body within
  the compiler type-check budget. 35 tests pass.

FuelBoard/ContentView.swift

@@ -144,16 +144,7 @@ struct ContentView: View {
             )
             .tabItem { Label("Alerts", systemImage: "bell.fill") }
 
-            SettingsView(
+            settingsTab
-                distanceUnit: $distanceUnit,
-                alertsFuel: alertsFuel,
-                alertsRadiusKM: alertsRadius,
-                testAlertResult: monitor.lastTestResult,
-                onTestAlert: { monitor.sendTestNotification() },
-                onPlainTestAlert: { monitor.sendPlainTestNotification() },
-                onShowOnboarding: { showOnboarding = true }
-            )
-            .tabItem { Label("Settings", systemImage: "gearshape.fill") }
         }
         .fullScreenCover(isPresented: $showOnboarding) {
             OnboardingView {
@@ -255,6 +246,23 @@ struct ContentView: View {
         }
     }
 
+    /// The Settings tab, extracted from `body` so the TabView expression stays
+    /// within the compiler's type-check budget.
+    private var settingsTab: some View {
+        SettingsView(
+            distanceUnit: $distanceUnit,
+            alertsFuel: alertsFuel,
+            alertsRadiusKM: alertsRadius,
+            testAlertResult: monitor.lastTestResult,
+            onTestAlert: { monitor.sendTestNotification() },
+            onPlainTestAlert: { monitor.sendPlainTestNotification() },
+            onRefreshDebugStatus: { monitor.refreshDebugStatus() },
+            onShowOnboarding: { showOnboarding = true },
+            debugStatus: monitor.debugStatus
+        )
+        .tabItem { Label("Settings", systemImage: "gearshape.fill") }
+    }
+
     private func toggleFavourite(_ station: FuelStation, fuel: FuelType) {
         let key = FavouriteEntry(station: station, fuel: fuel)
         if favourites.contains(where: { $0.id == key.id }) {

FuelBoard/ProximityMonitor.swift

@@ -4,6 +4,20 @@ import SwiftUI
 import MapKit
 import UIKit
 
+/// Debug-only location snapshot shown in Settings → Debug. Lets the
+/// developer verify location services while testing: the last fix (with age)
+/// plus how many stations selling the monitored fuel are within the alert
+/// radius of that fix — the exact criteria live alerts use.
+struct DebugLocationStatus: Equatable {
+    var coordinate: Coordinate?
+    var fixAge: TimeInterval?
+    var fuel: FuelType
+    var radiusKM: Double
+    var inRangeCount: Int
+    var cheapestInRange: FuelStation?
+    var cheapestDistanceKM: Double?
+}
+
 /// A station the user wants to see on a map — set when a notification tap
 /// can't hand off to Apple Maps (e.g. inside LiveContainer), so the app shows
 /// an in-app map with directions instead.
@@ -33,6 +47,9 @@ final class ProximityMonitor: NSObject, ObservableObject, @preconcurrency CLLoca
     @Published var lastAlert: String?
     @Published private(set) var lastTestResult: String?
     @Published var pendingStationMap: StationMapRequest?
+    /// Debug-only snapshot for the Settings → Debug section. Recomputed on
+    /// every location/stations change via `refreshDebugStatus()`.
+    @Published private(set) var debugStatus: DebugLocationStatus?
 
     private let manager = CLLocationManager()
     private var stations: [FuelStation] = []
@@ -76,6 +93,8 @@ final class ProximityMonitor: NSObject, ObservableObject, @preconcurrency CLLoca
         self.fuel = fuel
         self.radiusKM = radiusKM
 
+        refreshDebugStatus()
+
         for region in manager.monitoredRegions {
             manager.stopMonitoring(for: region)
         }
@@ -128,6 +147,33 @@ final class ProximityMonitor: NSObject, ObservableObject, @preconcurrency CLLoca
 
     var isEnabled: Bool { enabled }
 
+    /// Recomputes the Settings → Debug location snapshot from current state.
+    /// "In range" uses the SAME criteria as live alerts: stations selling the
+    /// monitored fuel within the alert radius of the last known location.
+    func refreshDebugStatus() {
+        guard let fix = FuelStore.loadLocationWithDate() else {
+            debugStatus = DebugLocationStatus(
+                coordinate: nil, fixAge: nil,
+                fuel: fuel, radiusKM: radiusKM,
+                inRangeCount: 0, cheapestInRange: nil, cheapestDistanceKM: nil)
+            return
+        }
+        let sellers = stations.filter { $0.prices[fuel] != nil }
+        let inRange = sellers.filter {
+            $0.distanceKM(to: fix.coordinate.lat, lng2: fix.coordinate.lng) <= radiusKM
+        }
+        let cheapest = inRange.min { ($0.prices[fuel] ?? .infinity) < ($1.prices[fuel] ?? .infinity) }
+        let cheapestDistance = cheapest.map {
+            $0.distanceKM(to: fix.coordinate.lat, lng2: fix.coordinate.lng)
+        }
+        debugStatus = DebugLocationStatus(
+            coordinate: fix.coordinate,
+            fixAge: Date().timeIntervalSince(fix.date),
+            fuel: fuel, radiusKM: radiusKM,
+            inRangeCount: inRange.count,
+            cheapestInRange: cheapest, cheapestDistanceKM: cheapestDistance)
+    }
+
     private func requestPermissions() {
         // Region monitoring needs Always location for background delivery.
         switch manager.authorizationStatus {

FuelBoard/SettingsView.swift

@@ -24,7 +24,11 @@ struct SettingsView: View {
     /// Drives the plain test (no criteria) — routed to the live monitor so it
     /// can carry a real station's name, price and coordinates.
     var onPlainTestAlert: () -> Void = {}
+    /// Recomputes the debug location snapshot (coordinates + in-range count).
+    var onRefreshDebugStatus: () -> Void = {}
     var onShowOnboarding: () -> Void = {}
+    /// Live snapshot of the device fix + stations in range (from the monitor).
+    var debugStatus: DebugLocationStatus?
 
     @StateObject private var tipStore = TipStore()
     @State private var showTipAlert = false
@@ -88,11 +92,13 @@ struct SettingsView: View {
                         } label: {
                             Label("Send plain test notification", systemImage: "bell.slash.fill")
                         }
+                        debugLocationRows
                     } header: {
                         Text("Debug")
                     } footer: {
                         Text("The first button applies the real criteria — cheapest \(alertsFuel.displayName.lowercased()) station within \(distanceUnit.format(alertsRadiusKM)) of you — and sends the actual station's name, price and coordinates. The second fires with no criteria at all (nearest seller), still carrying a real station, just to verify a notification appears and tapping it opens directions.")
                     }
+                    .onAppear { onRefreshDebugStatus() }
                 }
 
                 Section {
@@ -146,6 +152,100 @@ struct SettingsView: View {
         }
     }
 
+    /// Debug location block: device coordinates + fix age, then the in-range
+    /// indicator. "In range" mirrors the live alert criteria — stations selling
+    /// the monitored fuel within the alert radius of the last fix.
+    @ViewBuilder
+    private var debugLocationRows: some View {
+        Divider()
+        if let status = debugStatus {
+            HStack {
+                Label("Device", systemImage: "location.fill")
+                Spacer()
+                if let coord = status.coordinate {
+                    Text(String(format: "%.5f, %.5f", coord.lat, coord.lng))
+                        .font(.footnote)
+                        .monospacedDigit()
+                        .foregroundStyle(.secondary)
+                } else {
+                    Text("No fix")
+                        .foregroundStyle(.secondary)
+                }
+            }
+            if let age = status.fixAge {
+                HStack {
+                    Label("Fix age", systemImage: "clock.fill")
+                    Spacer()
+                    Text(ageText(age))
+                        .font(.footnote)
+                        .foregroundStyle(.secondary)
+                }
+            }
+            HStack {
+                Label("In range", systemImage: "location.circle.fill")
+                Spacer()
+                HStack(spacing: 6) {
+                    if let coord = status.coordinate {
+                        Circle()
+                            .fill(inRangeColor(status.inRangeCount))
+                            .frame(width: 10, height: 10)
+                    } else {
+                        Circle()
+                            .fill(.gray)
+                            .frame(width: 10, height: 10)
+                    }
+                    Text(inRangeText(status))
+                        .font(.footnote)
+                        .foregroundStyle(.secondary)
+                }
+            }
+            if let cheapest = status.cheapestInRange {
+                HStack {
+                    Label("Cheapest in range", systemImage: "fuelpump.fill")
+                    Spacer()
+                    Text(cheapestText(cheapest, fuel: status.fuel, distance: status.cheapestDistanceKM))
+                        .font(.footnote)
+                        .monospacedDigit()
+                        .foregroundStyle(.secondary)
+                }
+            }
+        } else {
+            HStack {
+                Label("Device", systemImage: "location.fill")
+                Spacer()
+                Text("—")
+                    .foregroundStyle(.secondary)
+            }
+        }
+    }
+
+    private func inRangeColor(_ count: Int) -> Color {
+        count > 0 ? .green : .red
+    }
+
+    private func inRangeText(_ status: DebugLocationStatus) -> String {
+        guard status.coordinate != nil else { return "waiting for fix" }
+        let fuelName = status.fuel.displayName.lowercased()
+        if status.inRangeCount == 1 {
+            return "1 \(fuelName) station within \(distanceUnit.format(status.radiusKM))"
+        }
+        return "\(status.inRangeCount) \(fuelName) stations within \(distanceUnit.format(status.radiusKM))"
+    }
+
+    private func cheapestText(_ station: FuelStation, fuel: FuelType, distance: Double?) -> String {
+        let price = station.prices[fuel].map { String(format: "%.1fp", $0) } ?? "—"
+        if let distance {
+            return "\(station.name) · \(distanceUnit.format(distance)) · \(price)"
+        }
+        return "\(station.name) · \(price)"
+    }
+
+    private func ageText(_ age: TimeInterval) -> String {
+        if age < 60 { return "\(Int(age))s ago" }
+        if age < 3600 { return "\(Int(age / 60))m \(Int(age.truncatingRemainder(dividingBy: 60)))s ago" }
+        return "\(Int(age / 3600))h \(Int((age.truncatingRemainder(dividingBy: 3600)) / 60))m ago"
+    }
+
     private var appVersion: String {
         let version = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String ?? "1.0"
         let build = Bundle.main.object(forInfoDictionaryKey: "CFBundleVersion") as? String ?? "1"

Shared/FuelStore.swift

@@ -326,6 +326,15 @@ struct FuelStore {
         return Coordinate(lat: parts[0], lng: parts[1])
     }
 
+    /// Location + the timestamp it was saved, for debug display (fix age).
+    static func loadLocationWithDate() -> (coordinate: Coordinate, date: Date)? {
+        let raw = loadString(service: locationKey)
+        let parts = raw?.split(separator: ",").compactMap { Double($0) }
+        guard let parts, parts.count == 3 else { return nil }
+        return (Coordinate(lat: parts[0], lng: parts[1]),
+                Date(timeIntervalSince1970: parts[2]))
+    }
+
     static func saveLocation(lat: Double, lng: Double, date: Date = Date()) {
         saveString("\(lat),\(lng),\(date.timeIntervalSince1970)", service: locationKey)
     }