Fix fast location cadence ref:

lib/screens/settings_screen.dart

@@ -480,7 +480,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
           keyboardType: TextInputType.number,
           decoration: const InputDecoration(
             labelText: 'Seconds',
-            helperText: 'Valid range: 10 to 31 seconds',
+            helperText: 'Fixed at 60 seconds',
           ),
         ),
         actions: [
@@ -492,7 +492,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
             onPressed: () {
               final parsed = int.tryParse(controller.text.trim());
               if (parsed == null) return;
-              Navigator.pop(context, parsed.clamp(10, 31));
+              Navigator.pop(context, parsed.clamp(60, 60));
             },
             child: const Text('Save'),
           ),

lib/services/location_tracking_service.dart

@@ -22,12 +22,18 @@ import 'profiles_feature_service.dart';
 class LocationTrackingService {
   static const double _defaultFastLocationMovementThresholdMeters = 10.0;
   static const double _minFastLocationMovementThresholdMeters = 10.0;
-  static const int _defaultFastLocationActiveCadenceSeconds = 10;
-  static const int _minFastLocationActiveCadenceSeconds = 10;
-  static const int _maxFastLocationActiveCadenceSeconds = 31;
-  static const Duration _fastLocationMinimumUpdateInterval = Duration(
-    seconds: 31,
+  static const int _defaultFastLocationActiveCadenceSeconds = 60;
+  static const int _minFastLocationActiveCadenceSeconds = 60;
+  static const int _maxFastLocationActiveCadenceSeconds = 60;
+  static const Duration _fastLocationSlowInterval = Duration(
+    seconds: 60,
   );
+  static const Duration _fastLocationWalkingInterval = Duration(seconds: 30);
+  static const Duration _fastLocationFastInterval = Duration(seconds: 15);
+  static const Duration _fastLocationVeryFastInterval = Duration(seconds: 5);
+  static const double _fastLocationIdleSpeedMaxMetersPerSecond = 0.75;
+  static const double _fastLocationWalkingSpeedMaxMetersPerSecond = 1.8;
+  static const double _fastLocationFastSpeedMaxMetersPerSecond = 4.0;
   // ============================================================================
   // Singleton Pattern
   // ============================================================================
@@ -599,11 +605,6 @@ class LocationTrackingService {
     final now = DateTime.now();
     final previous = _lastFastLocationSentPosition;
     final previousTime = _lastFastLocationSentAt;
-    if (previousTime != null &&
-        now.difference(previousTime) < _fastLocationMinimumUpdateInterval) {
-      return;
-    }
-
     if (previous != null && previousTime != null) {
       final distance = Geolocator.distanceBetween(
         previous.latitude,
@@ -612,9 +613,19 @@ class LocationTrackingService {
         position.longitude,
       );
       final elapsedMs = now.difference(previousTime).inMilliseconds;
+      final minimumInterval = _fastLocationMinimumIntervalFor(
+        distanceMeters: distance,
+        elapsedMs: elapsedMs,
+      );
+      if (elapsedMs < minimumInterval.inMilliseconds) {
+        return;
+      }
       if (distance < 1.0 && elapsedMs < 3000) {
         return;
       }
+    } else if (previousTime != null &&
+        now.difference(previousTime) < _fastLocationSlowInterval) {
+      return;
     }
 
     _lastFastLocationSentPosition = position;
@@ -622,6 +633,26 @@ class LocationTrackingService {
     onFastLocationUpdate?.call(position, reason);
   }
 
+  Duration _fastLocationMinimumIntervalFor({
+    required double distanceMeters,
+    required int elapsedMs,
+  }) {
+    if (elapsedMs <= 0) {
+      return _fastLocationSlowInterval;
+    }
+    final speedMetersPerSecond = distanceMeters / (elapsedMs / 1000.0);
+    if (speedMetersPerSecond < _fastLocationIdleSpeedMaxMetersPerSecond) {
+      return _fastLocationSlowInterval;
+    }
+    if (speedMetersPerSecond < _fastLocationWalkingSpeedMaxMetersPerSecond) {
+      return _fastLocationWalkingInterval;
+    }
+    if (speedMetersPerSecond < _fastLocationFastSpeedMaxMetersPerSecond) {
+      return _fastLocationFastInterval;
+    }
+    return _fastLocationVeryFastInterval;
+  }
+
   // ============================================================================
   // Mesh Network Broadcasting
   // ============================================================================

test/services/location_tracking_service_test.dart

@@ -15,7 +15,7 @@ void main() {
     );
     service.fastLocationUpdatesEnabled = false;
     service.fastLocationMovementThresholdMeters = 10.0;
-    service.fastLocationActiveCadenceSeconds = 10;
+    service.fastLocationActiveCadenceSeconds = 60;
     service.fastLocationChannelIdx = null;
   });
 
@@ -23,7 +23,7 @@ void main() {
     await service.loadSettings();
 
     expect(service.fastLocationMovementThresholdMeters, 10.0);
-    expect(service.fastLocationActiveCadenceSeconds, 10);
+    expect(service.fastLocationActiveCadenceSeconds, 60);
   });
 
   test('persists and restores fast location channel idx', () async {
@@ -50,6 +50,6 @@ void main() {
     await service.updateFastLocationActiveCadenceSeconds(45);
 
     expect(service.fastLocationMovementThresholdMeters, 10.0);
-    expect(service.fastLocationActiveCadenceSeconds, 31);
+    expect(service.fastLocationActiveCadenceSeconds, 60);
   });
 }