V3-07: route drawing (pins and straight lines)

Route plans are their own entity (RoutePlan/Waypoint, schema v3), never joined into ride totals or the rides list. RoutePlanRepository recomputes straight-line distance after every waypoint mutation. RoutePlannerScreen supports tap-to-add, tap-to-delete, and hand-rolled drag-to-move via MapCamera's screen/latlng conversions.

Fixed a real bug found by testing: FlutterMap's initialCenter/initialZoom are read once at construction, so building the map before the waypoints stream's first emission froze the camera on null-island. Also documents a genuine ten-minute test hang traced to Stream.first on a Drift watch() query inside testWidgets, which needs a pump-driven Timer that flutter_test's fake zone never advances on its own.

lib/src/domain/models.dart

@@ -225,3 +225,86 @@ class RideStats {
   int get durationMillis =>
       pointCount == 0 ? 0 : lastTimestamp - firstTimestamp;
 }
+
+/// A planned ride, sketched before setting off. See V3-07 in `docs/v3/`.
+///
+/// Deliberately **not** a [Trip] and never joined into ride totals or the rides list — a
+/// plan is not a recording, and conflating them would put unridden kilometres into ride
+/// totals. [distanceM] is the straight-line sum between waypoints in this ticket;
+/// [geometry] and [estimatedMillis] stay null until V3-08 adds road-snapped routing.
+class RoutePlan {
+  const RoutePlan({
+    this.id = 0,
+    required this.name,
+    required this.createdAt,
+    this.activity = Activity.motorcycle,
+    this.distanceM = 0.0,
+    this.estimatedMillis,
+    this.geometry,
+  });
+
+  final int id;
+  final String name;
+  final int createdAt;
+  final Activity activity;
+  final double distanceM;
+
+  /// Null until V3-08 fills it in from a routing engine.
+  final int? estimatedMillis;
+
+  /// Null until V3-08. This ticket's polyline is drawn straight between waypoints and
+  /// never stored -- it is fully derived from them, so there is nothing to persist.
+  final String? geometry;
+
+  RoutePlan copyWith({
+    int? id,
+    String? name,
+    int? createdAt,
+    Activity? activity,
+    double? distanceM,
+    int? estimatedMillis,
+    String? geometry,
+  }) => RoutePlan(
+    id: id ?? this.id,
+    name: name ?? this.name,
+    createdAt: createdAt ?? this.createdAt,
+    activity: activity ?? this.activity,
+    distanceM: distanceM ?? this.distanceM,
+    estimatedMillis: estimatedMillis ?? this.estimatedMillis,
+    geometry: geometry ?? this.geometry,
+  );
+}
+
+/// One pin on a [RoutePlan].
+///
+/// Ordered by [ordinal] rather than insertion id, so a pin can be dragged into a new
+/// position without touching every other row's identity.
+class Waypoint {
+  const Waypoint({
+    this.id = 0,
+    required this.routeId,
+    required this.ordinal,
+    required this.latitude,
+    required this.longitude,
+    this.name,
+  });
+
+  final int id;
+  final int routeId;
+  final int ordinal;
+  final double latitude;
+  final double longitude;
+
+  /// Null means the UI derives a label from [ordinal] ("Point 3"). Never store an empty
+  /// string -- the same rule as [Trip.name].
+  final String? name;
+
+  Waypoint copyWith({int? id, int? routeId, int? ordinal}) => Waypoint(
+    id: id ?? this.id,
+    routeId: routeId ?? this.routeId,
+    ordinal: ordinal ?? this.ordinal,
+    latitude: latitude,
+    longitude: longitude,
+    name: name,
+  );
+}