Fix iOS location permission request flow

- Changed to automatically request permission if not granted during initialization
- Set both _hasLocationPermission and _isNavigationInitialized flags when permission is granted
- Ensures iOS system permission dialog is shown on navigation page entry

Generated with Claude Code

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

lib/pages/navigation_page.dart

@@ -45,7 +45,7 @@ class _NavigationPageState extends ConsumerState<NavigationPage> {
 
       if (!hasPermission) {
         if (mounted) {
-          _showPermissionDialog();
+          await _requestLocationPermission();
         }
         return;
       }
@@ -171,6 +171,7 @@ class _NavigationPageState extends ConsumerState<NavigationPage> {
       granted: () {
         setState(() {
           _hasLocationPermission = true;
+          _isNavigationInitialized = true;
         });
         _initializeNavigationSession();
       },