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.

test/widget_test.dart

@@ -218,6 +218,20 @@ void main() {
           reason: 'the button must actually invoke the callback that navigates');
     });
 
+    screenTest('a routes entry point exists and is wired (V3-07)', (tester) async {
+      var opened = false;
+      await tester.pumpWidget(
+        host(RecordScreen(onOpenRoutes: () => opened = true)),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.byKey(const Key('open-routes')), findsOneWidget);
+      await tester.tap(find.byKey(const Key('open-routes')));
+      await tester.pumpAndSettle();
+
+      expect(opened, isTrue);
+    });
+
     screenTest('the live map appears only while recording and the toggle is on '
         '(V3-04)', (tester) async {
       // Idle, toggle on: no trip to draw, so no map at all.