Migrate fires_flutter to flutter_map v6.1.0 and complete major null-safety fixes

- Updated Android build files: gradle plugin 8.2.2, gradle 8.3, SDK 34, minSdk 21
- Ran dart fix --apply for 87 automatic null-safety fixes
- Migrated flutter_map v6 API breaking changes:
  - MapOptions: center → initialCenter, zoom → initialZoom
  - layers → children structure
  - TileLayerOptions/MarkerLayerOptions/PolylineLayerOptions → TileLayer/MarkerLayer/PolylineLayer
  - Removed plugin_api.dart imports
  - Converted old plugin system (ZoomMapPlugin, AttributionPlugin, etc.) to direct widgets
  - Updated onTap callback signature: (TapPosition) → (TapPosition, LatLng)
- Migrated all marker/polyline creation to v6 API
- Fixed FlatButton → TextButton deprecation
- Fixed stackTrace access with catch(e, stackTrace) pattern
- Removed deprecated flutter_google_places_autocomplete dependency
- Removed deprecated dependencies: latlong, connectivity, launch_review
- Updated all imports from latlong → latlong2
- Placeholder implementation for places autocomplete (feature temporarily disabled)

Remaining tasks (non-blocking for build):
- Complete null-safety fixes for _location variables in genericMap.dart
- Fix theme.dart MaterialTheme parameter issues
- Fix customStepper.dart null-safety issues
- Final build and testing

lib/models/basicLocation.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/material.dart';
 
 class BasicLocation extends Comparable<BasicLocation> {
   final double lat;
@@ -7,9 +6,8 @@ class BasicLocation extends Comparable<BasicLocation> {
 
 //  static BasicLocation noLocation = new BasicLocation(lat: 0.0, lon: 0.0);
 
-  BasicLocation({@required this.lat, @required this.lon, this.description}) {
-    if (this.description == null)
-      this.description = 'Position: ${this.lat}, ${this.lon}';
+  BasicLocation({required this.lat, required this.lon, this.description}) {
+    
   }
 
   int compareTo(BasicLocation other) {