refactor(ui): 移除空壳行业资讯 Tab + Provider URL 去重

- SimpleSidebar: 移除空壳"行业资讯" Tab 和 Newspaper icon import
- ModelsAPI.tsx: AVAILABLE_PROVIDERS 引用 LLM_PROVIDER_URLS 常量
- models.ts: PROVIDER_DEFAULTS 引用 api-urls.ts，消除重复 URL 定义
- 所有 Provider URL 现在统一在 api-urls.ts 维护

desktop/src/components/SimpleSidebar.tsx

@@ -1,14 +1,14 @@
 /**
  * SimpleSidebar - Trae Solo 风格的简洁侧边栏
  *
- * 仅显示：对话列表 + 行业资讯
+ * 仅显示：对话列表
  * 底部：模式切换 + 设置
  */
 
 import { useState } from 'react';
 import {
-  MessageSquare, Settings, LayoutGrid,
-  Search, X, Newspaper,
+  Settings, LayoutGrid,
+  Search, X,
 } from 'lucide-react';
 import { ConversationList } from './ConversationList';
 
@@ -17,10 +17,7 @@ interface SimpleSidebarProps {
   onToggleMode?: () => void;
 }
 
-type Tab = 'conversations' | 'news';
-
 export function SimpleSidebar({ onOpenSettings, onToggleMode }: SimpleSidebarProps) {
-  const [activeTab, setActiveTab] = useState<Tab>('conversations');
   const [searchQuery, setSearchQuery] = useState('');
 
   return (
@@ -32,68 +29,30 @@ export function SimpleSidebar({ onOpenSettings, onToggleMode }: SimpleSidebarPro
         </span>
       </div>
 
-      {/* Tab 切换: 对话 / 行业资讯 */}
-      <div className="flex border-b border-[#e8e6e1]/50 dark:border-gray-800">
-        <button
-          onClick={() => setActiveTab('conversations')}
-          className={`flex-1 flex items-center justify-center gap-1.5 py-2.5 text-xs font-medium transition-colors ${
-            activeTab === 'conversations'
-              ? 'text-gray-900 dark:text-gray-100 border-b-2 border-orange-500'
-              : 'text-gray-500 dark:text-gray-400 hover:text-gray-700 dark:hover:text-gray-300'
-          }`}
-        >
-          <MessageSquare className="w-3.5 h-3.5" />
-          对话
-        </button>
-        <button
-          onClick={() => setActiveTab('news')}
-          className={`flex-1 flex items-center justify-center gap-1.5 py-2.5 text-xs font-medium transition-colors ${
-            activeTab === 'news'
-              ? 'text-gray-900 dark:text-gray-100 border-b-2 border-orange-500'
-              : 'text-gray-500 dark:text-gray-400 hover:text-gray-700 dark:hover:text-gray-300'
-          }`}
-        >
-          <Newspaper className="w-3.5 h-3.5" />
-          行业资讯
-        </button>
-      </div>
-
       {/* 内容区域 */}
       <div className="flex-1 overflow-hidden">
-        {activeTab === 'conversations' && (
-          <div className="p-2 h-full overflow-y-auto">
-            {/* 搜索框 */}
-            <div className="relative mb-2">
-              <Search className="absolute left-3 top-1/2 -translate-y-1/2 text-gray-400 w-4 h-4" />
-              <input
-                type="text"
-                placeholder="搜索对话..."
-                value={searchQuery}
-                onChange={(e) => setSearchQuery(e.target.value)}
-                className="w-full pl-9 pr-8 py-1.5 bg-white/60 dark:bg-gray-800 border border-[#e8e6e1] dark:border-gray-700 rounded-lg text-sm focus:outline-none focus:border-gray-400 transition-all text-gray-700 dark:text-gray-300 placeholder-gray-400"
-              />
-              {searchQuery && (
-                <button
-                  onClick={() => setSearchQuery('')}
-                  className="absolute right-2 top-1/2 -translate-y-1/2 p-1 hover:bg-gray-200 dark:hover:bg-gray-700 rounded text-gray-400"
-                >
-                  <X className="w-3 h-3" />
-                </button>
-              )}
-            </div>
-            <ConversationList searchQuery={searchQuery} />
+        <div className="p-2 h-full overflow-y-auto">
+          {/* 搜索框 */}
+          <div className="relative mb-2">
+            <Search className="absolute left-3 top-1/2 -translate-y-1/2 text-gray-400 w-4 h-4" />
+            <input
+              type="text"
+              placeholder="搜索对话..."
+              value={searchQuery}
+              onChange={(e) => setSearchQuery(e.target.value)}
+              className="w-full pl-9 pr-8 py-1.5 bg-white/60 dark:bg-gray-800 border border-[#e8e6e1] dark:border-gray-700 rounded-lg text-sm focus:outline-none focus:border-gray-400 transition-all text-gray-700 dark:text-gray-300 placeholder-gray-400"
+            />
+            {searchQuery && (
+              <button
+                onClick={() => setSearchQuery('')}
+                className="absolute right-2 top-1/2 -translate-y-1/2 p-1 hover:bg-gray-200 dark:hover:bg-gray-700 rounded text-gray-400"
+              >
+                <X className="w-3 h-3" />
+              </button>
+            )}
           </div>
-        )}
-
-        {activeTab === 'news' && (
-          <div className="p-3 h-full overflow-y-auto">
-            <div className="flex flex-col items-center justify-center py-12 text-gray-400 dark:text-gray-500">
-              <Newspaper className="w-10 h-10 mb-3 opacity-50" />
-              <p className="text-sm">行业资讯</p>
-              <p className="text-xs mt-1">开发中，敬请期待</p>
-            </div>
-          </div>
-        )}
+          <ConversationList searchQuery={searchQuery} />
+        </div>
       </div>
 
       {/* 底部操作栏 */}