Added Line Of Sight Feature for repeater placement, Added app wide Units Setting (#198)

* feat: add LOS workflow, global units, l10n cleanup, and mobile UI overflow fixes

Squashes prior PR commits into one changeset including: LOS map/service/tests, global metric/imperial unit system adoption, notification/BLE safety fixes, app-wide localization backfill/mojibake cleanup, and responsive UI title/overflow hardening.

* l10n: revert unrelated locale churn for LOS feature

* feat: keep LOS with app-wide unit settings

* fix: resolve post-merge app bar/import analyzer errors

* style: format screen files for CI

lib/screens/app_settings_screen.dart

@@ -3,8 +3,10 @@ import 'package:provider/provider.dart';
 
 import '../connector/meshcore_connector.dart';
 import '../l10n/l10n.dart';
+import '../models/app_settings.dart';
 import '../services/app_settings_service.dart';
 import '../services/notification_service.dart';
+import '../widgets/adaptive_app_bar_title.dart';
 import 'map_cache_screen.dart';
 
 class AppSettingsScreen extends StatelessWidget {
@@ -14,7 +16,7 @@ class AppSettingsScreen extends StatelessWidget {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(
-        title: Text(context.l10n.appSettings_title),
+        title: AdaptiveAppBarTitle(context.l10n.appSettings_title),
         centerTitle: true,
       ),
       body: SafeArea(
@@ -360,6 +362,18 @@ class AppSettingsScreen extends StatelessWidget {
             onTap: () => _showTimeFilterDialog(context, settingsService),
           ),
           const Divider(height: 1),
+          ListTile(
+            leading: const Icon(Icons.straighten),
+            title: Text(context.l10n.appSettings_unitsTitle),
+            subtitle: Text(
+              settingsService.settings.unitSystem == UnitSystem.imperial
+                  ? context.l10n.appSettings_unitsImperial
+                  : context.l10n.appSettings_unitsMetric,
+            ),
+            trailing: const Icon(Icons.chevron_right),
+            onTap: () => _showUnitsDialog(context, settingsService),
+          ),
+          const Divider(height: 1),
           ListTile(
             leading: const Icon(Icons.download_outlined),
             title: Text(context.l10n.appSettings_offlineMapCache),
@@ -706,6 +720,46 @@ class AppSettingsScreen extends StatelessWidget {
     );
   }
 
+  void _showUnitsDialog(
+    BuildContext context,
+    AppSettingsService settingsService,
+  ) {
+    showDialog(
+      context: context,
+      builder: (context) => AlertDialog(
+        title: Text(context.l10n.appSettings_unitsTitle),
+        content: RadioGroup<UnitSystem>(
+          groupValue: settingsService.settings.unitSystem,
+          onChanged: (value) {
+            if (value != null) {
+              settingsService.setUnitSystem(value);
+              Navigator.pop(context);
+            }
+          },
+          child: Column(
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              ListTile(
+                title: Text(context.l10n.appSettings_unitsMetric),
+                leading: const Radio<UnitSystem>(value: UnitSystem.metric),
+              ),
+              ListTile(
+                title: Text(context.l10n.appSettings_unitsImperial),
+                leading: const Radio<UnitSystem>(value: UnitSystem.imperial),
+              ),
+            ],
+          ),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(context),
+            child: Text(context.l10n.common_close),
+          ),
+        ],
+      ),
+    );
+  }
+
   Widget _buildDebugCard(
     BuildContext context,
     AppSettingsService settingsService,