Add location-aware automatic default bounding box

The OpenSky "Default bounding box" now follows where flying happens.
A new "Automatic" picker mode (the default) resolves the live-map area
from a location cascade — drone telemetry → phone GPS → browser
geolocation → the user's Region country → Europe — instead of a fixed
box. Manual presets and Custom coordinates still work.

- Web App: new shared countries.js dataset (all countries + bbox,
  offline point→country); the bbox picker gains all European countries
  and an Automatic option (client pref prefs.autoBbox); the Region
  setting expands from 6 locale entries to all countries; the live map
  resolves the cascade each poll and sends it as ?bbox=.
- API Server: the states endpoint accepts and validates a ?bbox=
  override (validBBox); the Web App BFF forwards the query; the hub
  relays new phoneLatitude/phoneLongitude telemetry to the Web App.
- Fly App: reports the phone's own GPS (geolocator) alongside
  telemetry, used as the "your location" fallback.
- API panel: the OpenSky bbox picker lists all European countries.

Builds verified across web, panel, both Go modules and the Fly App
APK. Region list, Automatic default and the cascade ?bbox= override
verified in the browser.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Fly App/lib/flight_model.dart

@@ -21,6 +21,10 @@ class FlightModel extends ChangeNotifier {
   double? altitude;
   double? latitude;
   double? longitude;
+  // Phone's own GPS (independent of the drone's fix above); streamed to the
+  // server as a location fallback for the Web App's automatic bounding box.
+  double? phoneLatitude;
+  double? phoneLongitude;
   int? batteryPercent;
 
   UploadStatus upload = UploadStatus.disabled;

Fly App/lib/main.dart

@@ -2,6 +2,7 @@ import 'dart:async';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:geolocator/geolocator.dart';
 
 import 'dji_service.dart';
 import 'flight_model.dart';
@@ -46,6 +47,7 @@ class _HomePageState extends State<HomePage> {
   final FlightModel _model = FlightModel();
   StreamSubscription<Map<String, dynamic>>? _sub;
   StreamSubscription<AuthStatus>? _authSub;
+  StreamSubscription<Position>? _phoneLocSub;
 
   // Streams telemetry to the API Server and receives commands back.
   late final ServerUploader _uploader;
@@ -69,6 +71,43 @@ class _HomePageState extends State<HomePage> {
       if (mounted) setState(() {});
     });
     _init();
+    _startPhoneLocation();
+  }
+
+  /// Streams the phone's own GPS (coarse, low-frequency) and reports it to the
+  /// server as a telemetry field — a location fallback for the Web App's auto
+  /// bounding box when the drone has no fix. Best-effort: silently gives up if
+  /// location services or permission are unavailable.
+  Future<void> _startPhoneLocation() async {
+    try {
+      if (!await Geolocator.isLocationServiceEnabled()) return;
+      LocationPermission perm = await Geolocator.checkPermission();
+      if (perm == LocationPermission.denied) {
+        perm = await Geolocator.requestPermission();
+      }
+      if (perm == LocationPermission.denied || perm == LocationPermission.deniedForever) {
+        return;
+      }
+      _phoneLocSub = Geolocator.getPositionStream(
+        locationSettings: const LocationSettings(
+          accuracy: LocationAccuracy.low, // country-level is all the bbox needs
+          distanceFilter: 1000, // metres — infrequent updates
+        ),
+      ).listen((Position pos) {
+        _model.phoneLatitude = pos.latitude;
+        _model.phoneLongitude = pos.longitude;
+        _model.bump();
+        // Report to the server (rides the existing telemetry channel; only the
+        // phone fields are present, so it never disturbs drone telemetry).
+        _uploader.onEvent(<String, dynamic>{
+          'type': 'telemetry',
+          'phoneLatitude': pos.latitude,
+          'phoneLongitude': pos.longitude,
+        });
+      });
+    } catch (_) {
+      // Location plugin/permission unavailable — non-fatal.
+    }
   }
 
   Future<void> _init() async {
@@ -195,6 +234,8 @@ class _HomePageState extends State<HomePage> {
     if (_model.altitude != null) tel['altitude'] = _model.altitude;
     if (_model.latitude != null) tel['latitude'] = _model.latitude;
     if (_model.longitude != null) tel['longitude'] = _model.longitude;
+    if (_model.phoneLatitude != null) tel['phoneLatitude'] = _model.phoneLatitude;
+    if (_model.phoneLongitude != null) tel['phoneLongitude'] = _model.phoneLongitude;
     if (tel.length > 1) events.add(tel);
     return events;
   }
@@ -235,6 +276,7 @@ class _HomePageState extends State<HomePage> {
   void dispose() {
     _sub?.cancel();
     _authSub?.cancel();
+    _phoneLocSub?.cancel();
     _uploadSub?.cancel();
     _uploader.dispose();
     _serverHost.dispose();