feat(oauth): implement custom OAuth provider management #1106

- Add support for custom OAuth providers, including creation, retrieval, updating, and deletion.
- Introduce new model and controller for managing custom OAuth providers.
- Enhance existing OAuth logic to accommodate custom providers.
- Update API routes for custom OAuth provider management.
- Include i18n support for custom OAuth-related messages.

web/src/helpers/api.js

@@ -294,6 +294,48 @@ export async function onLinuxDOOAuthClicked(
   );
 }
 
+/**
+ * Initiate custom OAuth login
+ * @param {Object} provider - Custom OAuth provider config from status API
+ * @param {string} provider.slug - Provider slug (used for callback URL)
+ * @param {string} provider.client_id - OAuth client ID
+ * @param {string} provider.authorization_endpoint - Authorization URL
+ * @param {string} provider.scopes - OAuth scopes (space-separated)
+ * @param {Object} options - Options
+ * @param {boolean} options.shouldLogout - Whether to logout first
+ */
+export async function onCustomOAuthClicked(provider, options = {}) {
+  const state = await prepareOAuthState(options);
+  if (!state) return;
+  
+  try {
+    const redirect_uri = `${window.location.origin}/oauth/${provider.slug}`;
+    
+    // Check if authorization_endpoint is a full URL or relative path
+    let authUrl;
+    if (provider.authorization_endpoint.startsWith('http://') || 
+        provider.authorization_endpoint.startsWith('https://')) {
+      authUrl = new URL(provider.authorization_endpoint);
+    } else {
+      // Relative path - this is a configuration error, show error message
+      console.error('Custom OAuth authorization_endpoint must be a full URL:', provider.authorization_endpoint);
+      showError('OAuth 配置错误：授权端点必须是完整的 URL（以 http:// 或 https:// 开头）');
+      return;
+    }
+    
+    authUrl.searchParams.set('client_id', provider.client_id);
+    authUrl.searchParams.set('redirect_uri', redirect_uri);
+    authUrl.searchParams.set('response_type', 'code');
+    authUrl.searchParams.set('scope', provider.scopes || 'openid profile email');
+    authUrl.searchParams.set('state', state);
+    
+    window.open(authUrl.toString());
+  } catch (error) {
+    console.error('Failed to initiate custom OAuth:', error);
+    showError('OAuth 登录失败：' + (error.message || '未知错误'));
+  }
+}
+
 let channelModels = undefined;
 export async function loadChannelModels() {
   const res = await API.get('/api/models');