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/pubspec.lock

@@ -73,6 +73,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.19.1"
+  crypto:
+    dependency: transitive
+    description:
+      name: crypto
+      sha256: c8ea0233063ba03258fbcf2ca4d6dadfefe14f02fab57702265467a19f27fadf
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.7"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -105,6 +113,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "7.0.1"
+  fixnum:
+    dependency: transitive
+    description:
+      name: fixnum
+      sha256: b6dc7065e46c974bc7c5f143080a6764ec7a4be6da1285ececdc37be96de53be
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -144,6 +160,54 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  geolocator:
+    dependency: "direct main"
+    description:
+      name: geolocator
+      sha256: f62bcd90459e63210bbf9c35deb6a51c521f992a78de19a1fe5c11704f9530e2
+      url: "https://pub.dev"
+    source: hosted
+    version: "13.0.4"
+  geolocator_android:
+    dependency: transitive
+    description:
+      name: geolocator_android
+      sha256: fcb1760a50d7500deca37c9a666785c047139b5f9ee15aa5469fae7dbbe3170d
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.6.2"
+  geolocator_apple:
+    dependency: transitive
+    description:
+      name: geolocator_apple
+      sha256: "853803d6bb1713c094e935b4a5ae5f19c0308acf81da13fa9ff84fb4c70c0b73"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.14"
+  geolocator_platform_interface:
+    dependency: transitive
+    description:
+      name: geolocator_platform_interface
+      sha256: cdb082e4f048b69da244117b7914cc60d2a8897546ffaa4f2529c786ded7aee2
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.2.8"
+  geolocator_web:
+    dependency: transitive
+    description:
+      name: geolocator_web
+      sha256: "19e485a0f8d6a88abcf9c53cba3a4105e14b7435ed8ac1c108c067b938fe8429"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.1.4"
+  geolocator_windows:
+    dependency: transitive
+    description:
+      name: geolocator_windows
+      sha256: "175435404d20278ffd220de83c2ca293b73db95eafbdc8131fe8609be1421eb6"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.5"
   image:
     dependency: transitive
     description:
@@ -437,6 +501,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.7.11"
+  typed_data:
+    dependency: transitive
+    description:
+      name: typed_data
+      sha256: f9049c039ebfeb4cf7a7104a675823cd72dba8297f264b6637062516699fa006
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.4.0"
+  uuid:
+    dependency: transitive
+    description:
+      name: uuid
+      sha256: "1fef9e8e11e2991bb773070d4656b7bd5d850967a2456cfc83cf47925ba79489"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.5.3"
   vector_math:
     dependency: transitive
     description: