V3-04: live map on the recording screen

Feeds RideMap from watchPointsForTrip/watchSegmentsForTrip via autoDispose.family providers. RecordingEngine stays map-free (enforced by architecture_test.dart). RideMap gained lifecycle-aware tile teardown and follow-mode, both shared with the trip-detail map.

test/architecture_test.dart

@@ -0,0 +1,15 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+
+/// A structural invariant from V3-04, checked directly rather than trusted: rendering
+/// belongs to a visible screen's widget lifecycle, never to the recording engine. If this
+/// ever starts failing, a map reference has leaked into code that keeps running while the
+/// phone is pocketed and the screen is off.
+void main() {
+  test('RecordingEngine never imports the map', () {
+    final source = File('lib/src/recording/recording_engine.dart').readAsStringSync();
+    expect(source.contains('ride_map'), isFalse);
+    expect(source.contains('flutter_map'), isFalse);
+  });
+}