fix: SearXNG 搜索引擎参数去掉默认值，留空使用实例默认引擎

src/renderer/components/searxng-modal.ts

@@ -11,7 +11,7 @@ import { logInfo, logSuccess } from '../services/log-service.js';
 const DEFAULTS = {
   enabled: false,
   url: '',
-  engines: 'google,bing,duckduckgo,wikipedia',
+  engines: '',
   language: 'zh-CN',
   safesearch: 1,
   time_range: '',

src/renderer/index.html

@@ -739,7 +739,7 @@
 
             <div class="setting-group">
                 <label class="setting-label">搜索引擎</label>
-                <input class="setting-input" id="searxngEngines" type="text" placeholder="google,bing,duckduckgo,wikipedia" style="margin-bottom:6px;">
+                <input class="setting-input" id="searxngEngines" type="text" placeholder="留空使用实例默认引擎，逗号分隔" style="margin-bottom:6px;">
                 <p class="text-muted" style="font-size:11px;">逗号分隔的引擎列表。常用: google, bing, duckduckgo, wikipedia, brave, qwant, startpage</p>
             </div>