V3-05: mounted (handlebar) mode

Wake lock via a WakelockController seam (mirrors LocationSource), gated strictly to actual recording and released on stop/discard/navigate-away/dispose. High-contrast ripprMountedTheme() applied only to the record screen. BigStat gained a scale param for the headline figure rather than a blanket TextTheme.apply, which crashes on Material 3's default theme.

lib/src/config/config.dart

@@ -15,6 +15,7 @@ const _keyEndpoint = 'upload_endpoint';
 const _keyDeviceId = 'device_id';
 const _keyMapEnabled = 'map_enabled';
 const _keyUnitSystem = 'unit_system';
+const _keyMountedMode = 'mounted_mode';
 
 /// Countries that did not adopt metric for everyday distances. Not exhaustive — a
 /// best-effort default, not a claim of authority. Anyone can override it in Settings.
@@ -69,6 +70,14 @@ class Config {
         : UnitSystem.metric;
   }
 
+  /// V3-05: a mounted phone is a different product from a pocketed one -- kept awake,
+  /// higher contrast, bigger targets. Off by default; a pocketed ride is still the
+  /// common case.
+  bool get mountedMode => _prefs.getBool(_keyMountedMode) ?? false;
+
+  Future<void> setMountedMode(bool enabled) =>
+      _prefs.setBool(_keyMountedMode, enabled);
+
   /// Stable per-install id so a server can distinguish riders in a group.
   String get deviceId {
     final existing = _prefs.getString(_keyDeviceId);