Add flutter_lints and fix analyzer errors, dead code, and unused imports

lib/widgets/map/direction_cones.dart

@@ -6,7 +6,6 @@ import 'package:latlong2/latlong.dart';
 import '../../app_state.dart';
 import '../../dev_config.dart';
 import '../../models/osm_node.dart';
-import '../../models/direction_fov.dart';
 
 /// Helper class to build direction cone polygons for cameras
 class DirectionConesBuilder {
@@ -113,11 +112,6 @@ class DirectionConesBuilder {
            node.coord.longitude.abs() <= 180;
   }
 
-  static bool _isPendingUpload(OsmNode node) {
-    return node.tags.containsKey('_pending_upload') && 
-           node.tags['_pending_upload'] == 'true';
-  }
-
   /// Build cone with variable FOV width - new method for range notation support
   static Polygon _buildConeWithFov(
     LatLng origin, 
@@ -141,28 +135,6 @@ class DirectionConesBuilder {
     );
   }
 
-  /// Legacy method for backward compatibility - uses dev_config FOV
-  static Polygon _buildCone(
-    LatLng origin, 
-    double bearingDeg, 
-    double zoom, {
-    required BuildContext context,
-    bool isPending = false,
-    bool isSession = false,
-    bool isActiveDirection = true,
-  }) {
-    return _buildConeInternal(
-      origin: origin,
-      bearingDeg: bearingDeg,
-      halfAngleDeg: kDirectionConeHalfAngle,
-      zoom: zoom,
-      context: context,
-      isPending: isPending,
-      isSession: isSession,
-      isActiveDirection: isActiveDirection,
-    );
-  }
-
   /// Internal cone building method that handles the actual rendering
   static Polygon _buildConeInternal({
     required LatLng origin,

lib/widgets/map/map_data_manager.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
-import 'package:flutter_map_animations/flutter_map_animations.dart';
 import 'package:latlong2/latlong.dart';
 
 import '../../models/osm_node.dart';

lib/widgets/map/map_overlays.dart

@@ -1,12 +1,10 @@
 import 'package:flutter/material.dart';
-import 'package:flutter_map/flutter_map.dart';
 import 'package:flutter_map_animations/flutter_map_animations.dart';
 import 'package:provider/provider.dart';
 
 import '../../app_state.dart';
 import '../../dev_config.dart';
 import '../../services/localization_service.dart';
-import '../camera_icon.dart';
 import '../compass_indicator.dart';
 import 'layer_selector_button.dart';
 

lib/widgets/map/marker_layer_builder.dart

@@ -6,7 +6,6 @@ import 'package:latlong2/latlong.dart';
 import '../../models/osm_node.dart';
 import '../../models/suspected_location.dart';
 import '../../app_state.dart';
-import '../../state/session_state.dart';
 import '../../dev_config.dart';
 import '../camera_icon.dart';
 import '../provisional_pin.dart';

lib/widgets/map/node_markers.dart

@@ -20,8 +20,8 @@ class NodeMapMarker extends StatefulWidget {
     required this.mapController, 
     this.onNodeTap,
     this.enabled = true,
-    Key? key,
-  }) : super(key: key);
+    super.key,
+  });
 
   @override
   State<NodeMapMarker> createState() => _NodeMapMarkerState();

lib/widgets/map/node_refresh_controller.dart

@@ -1,7 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_map_animations/flutter_map_animations.dart';
 import 'package:flutter_map/flutter_map.dart';
-import 'package:latlong2/latlong.dart';
 
 import '../../models/node_profile.dart';
 import '../../app_state.dart' show UploadMode;

lib/widgets/map/suspected_location_markers.dart

@@ -20,8 +20,8 @@ class SuspectedLocationMapMarker extends StatefulWidget {
     required this.mapController, 
     this.onLocationTap,
     this.enabled = true,
-    Key? key,
-  }) : super(key: key);
+    super.key,
+  });
 
   @override
   State<SuspectedLocationMapMarker> createState() => _SuspectedLocationMapMarkerState();

lib/widgets/map/tile_layer_manager.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_map/flutter_map.dart';
-import 'package:latlong2/latlong.dart';
 
 import '../../models/tile_provider.dart' as models;
 import '../../services/deflock_tile_provider.dart';
@@ -93,7 +92,7 @@ class TileLayerManager {
     return TileLayer(
       urlTemplate: urlTemplate, // Critical for cache key generation
       userAgentPackageName: 'me.deflock.deflockapp',
-      maxZoom: selectedTileType?.maxZoom?.toDouble() ?? 18.0,
+      maxZoom: selectedTileType?.maxZoom.toDouble() ?? 18.0,
       tileProvider: _tileProvider!,
     );
   }