Add shared UI components for mesh application

- Introduced `mesh_ui.dart` with reusable widgets including SectionHeader, MeshCard, StatusChip, StatTile, AvatarCircle, SignalBars, RouteChip, PulseDot, BottomSheetHeader, ErrorRetryCard, and ListEntrance.
- Implemented `path_map_ui.dart` for path map screens, featuring path distance calculations, playback controls, and a summary list of observed paths.
- Created `themed_map_tile_layer.dart` for shared cached map tiles with automatic dark-mode treatment.

lib/models/display_path.dart

@@ -0,0 +1,69 @@
+import 'dart:ui';
+
+import 'package:latlong2/latlong.dart';
+
+import 'path_history.dart';
+
+/// One observed route rendered on the path map — the live traced path
+/// (primary) or an alternate from the contact's path history — resolved to
+/// map coordinates with per-hop confidence flags.
+class DisplayPath {
+  final String id;
+  final String label;
+  final Color color;
+  final bool isPrimary;
+
+  /// Outbound hop bytes, including hops that could not be placed on the map.
+  final List<int> hopBytes;
+
+  /// Resolved map points: self, each locatable hop, then the target when its
+  /// position is known. Hops with no position are skipped here but still
+  /// counted in [unresolvedHops].
+  final List<LatLng> points;
+
+  /// Display name for each entry of [points].
+  final List<String> pointLabels;
+
+  /// Whether each entry of [points] is a GPS-grade position (vs inferred).
+  final List<bool> pointConfirmed;
+
+  /// Per segment (length points-1): true when either endpoint is inferred or
+  /// unlocatable hops were skipped in between — rendered dashed.
+  final List<bool> segmentEstimated;
+
+  /// Per segment: the transmission ordinal of the segment's destination,
+  /// used to highlight the matching hop-list row during animation.
+  final List<int> rowForSegment;
+
+  /// Total transmissions on the full route (including unlocatable hops).
+  final int totalTransmissions;
+
+  /// True when the route ends with a chat-target endpoint row.
+  final bool hasTargetEndpoint;
+
+  final int gpsConfirmedHops;
+  final int unresolvedHops;
+  final double distanceMeters;
+
+  /// History metadata; null for the live traced (primary) path.
+  final PathRecord? record;
+
+  const DisplayPath({
+    required this.id,
+    required this.label,
+    required this.color,
+    required this.isPrimary,
+    required this.hopBytes,
+    required this.points,
+    required this.pointLabels,
+    required this.pointConfirmed,
+    required this.segmentEstimated,
+    required this.rowForSegment,
+    required this.totalTransmissions,
+    required this.hasTargetEndpoint,
+    required this.gpsConfirmedHops,
+    required this.unresolvedHops,
+    required this.distanceMeters,
+    this.record,
+  });
+}