fix(mobile): allow URL validation to pass when scheme is not provided

chore(mobile): add missing Belarusian (be) language option in settings

mobile/lib/constants/locales.dart

@@ -6,6 +6,7 @@ const Map<String, Locale> locales = {
   // Additional locales
   'Arabic (ar)': Locale('ar'),
   'Basque (eu)': Locale('eu'),
+  'Belarusian (be)': Locale('be'),
   'Bosnian (bl)': Locale('bn'),
   'Brazilian Portuguese (pt_BR)': Locale('pt', 'BR'),
   'Bulgarian (bg)': Locale('bg'),

mobile/lib/utils/url_helper.dart

@@ -10,6 +10,24 @@ String sanitizeUrl(String url) {
   return urlWithSchema.trimRight().replaceFirst(RegExp(r"/+$"), "");
 }
 
+/// Validates a user-entered server URL
+bool isValidServerUrl(String? url) {
+  if (url == null || url.isEmpty) {
+    return true;
+  }
+
+  if (!url.contains('://')) {
+    // Prepend conforming scheme for URL validation
+    // Uri.tryParse will not parse out host without a scheme provided, even though we assume http(s) when connecting
+    url = 'http://$url';
+  }
+
+  final parsedUrl = Uri.tryParse(url);
+  return parsedUrl != null &&
+      (parsedUrl.scheme.isEmpty || parsedUrl.scheme.startsWith(RegExp(r'https?'))) &&
+      parsedUrl.host.isNotEmpty;
+}
+
 String? getServerUrl() {
   final serverUrl = punycodeDecodeUrl(Store.tryGet(StoreKey.serverEndpoint));
   final serverUri = serverUrl != null ? Uri.tryParse(serverUrl) : null;

mobile/lib/widgets/forms/login/login_form.dart

@@ -43,18 +43,7 @@ class LoginForm extends HookConsumerWidget {
 
   final log = Logger('LoginForm');
 
-  String? _validateUrl(String? url) {
-    if (url == null || url.isEmpty) {
-      return null;
-    }
-
-    final parsedUrl = Uri.tryParse(url);
-    if (parsedUrl == null || !parsedUrl.isAbsolute || !parsedUrl.scheme.startsWith("http") || parsedUrl.host.isEmpty) {
-      return 'login_form_err_invalid_url'.tr();
-    }
-
-    return null;
-  }
+  String? _validateUrl(String? url) => isValidServerUrl(url) ? null : 'login_form_err_invalid_url'.tr();
 
   String? _validateEmail(String? email) {
     if (email == null || email == '') {

mobile/test/modules/utils/url_helper_test.dart

@@ -77,6 +77,40 @@ void main() {
     });
   });
 
+  group('isValidServerUrl', () {
+    test('should treat null as valid', () {
+      expect(isValidServerUrl(null), isTrue);
+    });
+
+    test('should treat empty string as valid', () {
+      expect(isValidServerUrl(''), isTrue);
+    });
+
+    test('should accept a bare host', () {
+      expect(isValidServerUrl('demo.immich.app'), isTrue);
+    });
+
+    test('should accept a bare host with a port', () {
+      expect(isValidServerUrl('192.168.1.1:2283'), isTrue);
+    });
+
+    test('should accept an http URL', () {
+      expect(isValidServerUrl('http://demo.immich.app'), isTrue);
+    });
+
+    test('should accept an https URL', () {
+      expect(isValidServerUrl('https://demo.immich.app:2283/api'), isTrue);
+    });
+
+    test('should reject a non-http scheme', () {
+      expect(isValidServerUrl('ftp://demo.immich.app'), isFalse);
+    });
+
+    test('should reject scheme only input', () {
+      expect(isValidServerUrl('https://'), isFalse);
+    });
+  });
+
   group('punycodeDecodeUrl', () {
     test('should return null for null input', () {
       expect(punycodeDecodeUrl(null), isNull);