feat: consolidate backend and docker-compose setup

lib/core/location/location_service.dart

@@ -0,0 +1,46 @@
+import 'package:flutter/foundation.dart';
+import 'package:geolocator/geolocator.dart';
+
+class LocationService {
+  static Future<Position?> Function()? mockDeterminator;
+
+  static Future<Position?> determinePosition() async {
+    if (mockDeterminator != null) {
+      return mockDeterminator!();
+    }
+    try {
+      bool serviceEnabled = await Geolocator.isLocationServiceEnabled();
+      if (!serviceEnabled) {
+        debugPrint('Location services are disabled.');
+        return null;
+      }
+
+      LocationPermission permission = await Geolocator.checkPermission();
+      if (permission == LocationPermission.denied) {
+        permission = await Geolocator.requestPermission();
+        if (permission == LocationPermission.denied) {
+          debugPrint('Location permission denied.');
+          return null;
+        }
+      }
+      
+      if (permission == LocationPermission.deniedForever) {
+        debugPrint('Location permission denied forever.');
+        return null;
+      } 
+
+      try {
+        return await Geolocator.getCurrentPosition(
+          desiredAccuracy: LocationAccuracy.high,
+          timeLimit: const Duration(seconds: 5),
+        );
+      } catch (e) {
+        debugPrint('getCurrentPosition failed: $e. Attempting getLastKnownPosition...');
+        return await Geolocator.getLastKnownPosition();
+      }
+    } catch (e) {
+      debugPrint('Error in LocationService: $e');
+      return null;
+    }
+  }
+}