Remove the ChatGPT sign-in from the AI providers panel

lib/config/constants.dart

@@ -47,9 +47,6 @@ class AppConstants {
       '$apiBase/settings/ai-providers/keys/$provider';
   static String settingsAiSelection(String role) =>
       '$apiBase/settings/ai-providers/selection/$role';
-  static const String settingsChatgptLogin = '$apiBase/settings/chatgpt-login';
-  static const String settingsChatgptLoginPoll =
-      '$apiBase/settings/chatgpt-login/poll';
   static const String channels = '$apiBase/channels';
   static const String channelSubscribe = '$apiBase/channels/subscribe';
   static const String channelSubscribeBulk = '$apiBase/channels/subscribe-bulk';

lib/models/ai_providers.dart

@@ -82,7 +82,7 @@ class AiProvidersStatus {
   final AiSelection embed;
   final AiSelection rank;
 
-  /// Per-provider "usable right now", including `chatgpt` (sign-in based).
+  /// Per-provider "usable right now" (anthropic / gemini / openai).
   final Map<String, bool> availability;
 
   factory AiProvidersStatus.fromJson(Map<String, dynamic> json) {
@@ -104,55 +104,3 @@ class AiProvidersStatus {
     );
   }
 }
-
-/// Status of the ChatGPT (Codex OAuth) sign-in.
-class ChatgptLoginStatus {
-  const ChatgptLoginStatus({
-    required this.connected,
-    required this.needsReauth,
-    required this.pending,
-    required this.userCode,
-    required this.verificationUrl,
-  });
-
-  final bool connected;
-  final bool needsReauth;
-  final bool pending;
-
-  /// Device code to enter (only while a sign-in is pending).
-  final String? userCode;
-  final String? verificationUrl;
-
-  factory ChatgptLoginStatus.fromJson(Map<String, dynamic> json) =>
-      ChatgptLoginStatus(
-        connected: json['connected'] == true,
-        needsReauth: json['needs_reauth'] == true,
-        pending: json['pending'] == true,
-        userCode: json['user_code'] as String?,
-        verificationUrl: json['verification_url'] as String?,
-      );
-}
-
-/// One poll of the device sign-in.
-class ChatgptPollResult {
-  const ChatgptPollResult({
-    required this.status,
-    required this.detail,
-    required this.userCode,
-    required this.verificationUrl,
-  });
-
-  /// idle | pending | connected | expired | error
-  final String status;
-  final String? detail;
-  final String? userCode;
-  final String? verificationUrl;
-
-  factory ChatgptPollResult.fromJson(Map<String, dynamic> json) =>
-      ChatgptPollResult(
-        status: (json['status'] as String?) ?? 'idle',
-        detail: json['detail'] as String?,
-        userCode: json['user_code'] as String?,
-        verificationUrl: json['verification_url'] as String?,
-      );
-}

lib/services/api_service.dart

@@ -531,36 +531,6 @@ class ApiService {
     return AiProvidersStatus.fromJson(r.data as Map<String, dynamic>);
   });
 
-  // --- ChatGPT (Codex OAuth) sign-in (admin) --------------------------------
-
-  Future<ChatgptLoginStatus> getChatgptLogin() => _guard(() async {
-    final r = await _dio.get('$_baseUrl${AppConstants.settingsChatgptLogin}');
-    return ChatgptLoginStatus.fromJson(r.data as Map<String, dynamic>);
-  });
-
-  Future<ChatgptPollResult> startChatgptLogin() => _guard(() async {
-    final r = await _dio.post('$_baseUrl${AppConstants.settingsChatgptLogin}');
-    // The start response has the same shape as a pending poll.
-    final data = r.data as Map<String, dynamic>;
-    return ChatgptPollResult(
-      status: 'pending',
-      detail: null,
-      userCode: data['user_code'] as String?,
-      verificationUrl: data['verification_url'] as String?,
-    );
-  });
-
-  Future<ChatgptPollResult> pollChatgptLogin() => _guard(() async {
-    final r = await _dio.post(
-      '$_baseUrl${AppConstants.settingsChatgptLoginPoll}',
-    );
-    return ChatgptPollResult.fromJson(r.data as Map<String, dynamic>);
-  });
-
-  Future<void> clearChatgptLogin() => _guard(() async {
-    await _dio.delete('$_baseUrl${AppConstants.settingsChatgptLogin}');
-  });
-
   /// Records an evictable cache claim on [videoId] and (server-side) kicks off
   /// its HQ download, without it showing in the Downloads tab. Called when the
   /// user starts instant playback of a not-yet-downloaded video so the player