Drop deprecated MapKit and ActivityKit calls, and a dead capture

- RoadDistanceService builds route endpoints with MKMapItem(location:address:)
  instead of the MKPlacemark path deprecated in iOS 26.
- LiveActivityManager updates through ActivityContent, replacing the
  ActivityKit update(using:) call deprecated in iOS 16.2.
- The location-update hook no longer captures an unused state object; the
  closure body already runs on self, so behaviour is unchanged.

FuelBoard/ContentView.swift

@@ -161,7 +161,7 @@ struct ContentView: View {
     }
 
     private func installLocationUpdateHook() {
-        locationManager.onLocationUpdate = { [weak monitor] in
+        locationManager.onLocationUpdate = {
             self.updateAlertMonitor()
             // The Live Activity follows the same wake-ups — this hook
             // fires on every fix incl. background significant-change

FuelBoard/LiveActivityManager.swift

@@ -79,7 +79,7 @@ enum LiveActivityManager {
                 currentStartDate = nil
                 start(attributes: attributes, state: state)
             } else {
-                Task { await current.update(using: state) }
+                Task { await current.update(ActivityContent(state: state, staleDate: nil)) }
             }
         } else {
             start(attributes: attributes, state: state)

FuelBoard/RoadDistanceService.swift

@@ -13,6 +13,7 @@
 // every row at once; the mode must also be ON for any pass to run at all.
 
 import Foundation
+import CoreLocation
 import MapKit
 import UIKit
 import WidgetKit
@@ -407,8 +408,14 @@ enum RoadDistanceService {
     /// Driving distance (metres) between two coordinates via Apple Maps routing.
     private static func roadMeters(from: CLLocationCoordinate2D, to: CLLocationCoordinate2D) async -> Double? {
         let request = MKDirections.Request()
-        request.source = MKMapItem(placemark: MKPlacemark(coordinate: from))
-        request.destination = MKMapItem(placemark: MKPlacemark(coordinate: to))
+        request.source = MKMapItem(
+            location: CLLocation(latitude: from.latitude, longitude: from.longitude),
+            address: nil
+        )
+        request.destination = MKMapItem(
+            location: CLLocation(latitude: to.latitude, longitude: to.longitude),
+            address: nil
+        )
         request.transportType = .automobile
         request.requestsAlternateRoutes = false
         do {