fix: update API URLs and improve error handling for SUB2API configuration

background/mail-2925-session.js

@@ -37,12 +37,10 @@
     const MAIL2925_COOKIE_DOMAINS = [
       '2925.com',
       'www.2925.com',
-      'mail2.xiyouji.com',
     ];
     const MAIL2925_COOKIE_ORIGINS = [
       'https://2925.com',
       'https://www.2925.com',
-      'https://mail2.xiyouji.com',
     ];
     const MAIL2925_LIMIT_ERROR_PREFIX = 'MAIL2925_LIMIT_REACHED::';
     const MAIL2925_THREAD_TERMINATED_ERROR_PREFIX = 'MAIL2925_THREAD_TERMINATED::';

background/navigation-utils.js

@@ -19,6 +19,7 @@
 
     function normalizeSub2ApiUrl(rawUrl) {
       const input = (rawUrl || '').trim() || DEFAULT_SUB2API_URL;
+      if (!input) return '';
       const withProtocol = /^https?:\/\//i.test(input) ? input : `https://${input}`;
       const parsed = new URL(withProtocol);
       if (!parsed.pathname || parsed.pathname === '/') {

background/panel-bridge.js

@@ -251,6 +251,9 @@
       const sub2apiUrl = normalizeSub2ApiUrl(state.sub2apiUrl);
       const groupName = (state.sub2apiGroupName || DEFAULT_SUB2API_GROUP_NAME).trim() || DEFAULT_SUB2API_GROUP_NAME;
 
+      if (!sub2apiUrl) {
+        throw new Error('SUB2API URL is not configured. Please fill it in the side panel first.');
+      }
       if (!state.sub2apiEmail) {
         throw new Error('尚未配置 SUB2API 登录邮箱，请先在侧边栏填写。');
       }

background/steps/platform-verify.js

@@ -343,6 +343,9 @@
       }
 
       const sub2apiUrl = normalizeSub2ApiUrl(state.sub2apiUrl);
+      if (!sub2apiUrl) {
+        throw new Error('SUB2API URL is not configured. Please fill it in the side panel first.');
+      }
       const injectFiles = ['content/utils.js', 'content/sub2api-panel.js'];
 
       await addStepLog(visibleStep, '正在打开 SUB2API 后台...');