feat(search): 点击放大镜切换搜索引擎

- 搜索框左侧图标改为触发器，点击展开效果五快捷栏
- 选中后左侧图标切换为对应引擎图标（本地放大镜 / Google / Bing / 百度 / 搜狗 / 360）
- 搜索框占位文案随当前模式变化，原有过滤与回车行为保留

stash-web/src/App.css

@@ -1444,42 +1444,37 @@ html.theme-transition .site-background {
   align-items: center;
 }
 
-.engine-toggle {
+.engine-trigger {
   display: inline-flex;
   align-items: center;
-  gap: 3px;
-  height: 24px;
-  padding: 0 var(--su-space-2);
-  border: 1px solid var(--su-border);
+  justify-content: center;
+  width: 26px;
+  height: 26px;
+  padding: 0;
+  border: 0;
   border-radius: var(--su-radius-xs);
-  background-color: var(--su-bg-subtle);
-  color: var(--su-text-sub);
-  font: inherit;
-  font-size: 11px;
-  line-height: 1;
+  background: transparent;
+  color: var(--su-text-muted);
   cursor: pointer;
   transition:
     color var(--su-duration-fast) var(--su-ease-in-out),
-    background-color var(--su-duration-fast) var(--su-ease-in-out),
-    border-color var(--su-duration-fast) var(--su-ease-in-out);
+    background-color var(--su-duration-fast) var(--su-ease-in-out);
 }
 
-.engine-toggle:hover,
-.engine-toggle[aria-expanded='true'] {
-  border-color: var(--su-border-strong);
-  background-color: var(--su-bg-hover);
+.engine-trigger:hover,
+.engine-trigger[aria-expanded='true'] {
+  background-color: var(--su-bg-subtle);
   color: var(--su-text-main);
 }
 
-.engine-toggle span {
-  font-size: 9px;
-  opacity: 0.6;
+.engine-trigger svg {
+  display: block;
 }
 
 .engine-menu {
   position: absolute;
   top: 50%;
-  right: calc(100% + 6px);
+  left: calc(100% + 6px);
   z-index: var(--su-z-float);
   display: flex;
   flex-direction: row;
@@ -1496,7 +1491,7 @@ html.theme-transition .site-background {
 @keyframes engine-bar-in {
   from {
     opacity: 0;
-    transform: translate(6px, -50%);
+    transform: translate(-6px, -50%);
   }
   to {
     opacity: 1;

stash-web/src/AppNext.tsx

@@ -1,5 +1,6 @@
 import {
   Empty,
+  Icon,
   Layout,
   Menu,
   Notice,
@@ -63,12 +64,42 @@ type Route =
   | { kind: 'api' }
 
 const SEARCH_ENGINES = [
-  { key: 'local', name: '本地', search: '' },
-  { key: 'google', name: 'Google', search: 'https://www.google.com/search?q=' },
-  { key: 'bing', name: 'Bing', search: 'https://www.bing.com/search?q=' },
-  { key: 'baidu', name: '百度', search: 'https://www.baidu.com/s?wd=' },
-  { key: 'sogou', name: '搜狗', search: 'https://www.sogou.com/web?query=' },
-  { key: '360', name: '360', search: 'https://www.so.com/s?q=' },
+  { key: 'local', name: '本地', search: '', path: '', color: '' },
+  {
+    key: 'google',
+    name: 'Google',
+    search: 'https://www.google.com/search?q=',
+    path: 'M12.24 10.285V14.4h6.806c-.275 1.765-2.056 5.174-6.806 5.174-4.095 0-7.439-3.389-7.439-7.574s3.345-7.574 7.439-7.574c2.33 0 3.891.989 4.785 1.849l3.254-3.138C18.189 1.186 15.479 0 12.24 0c-6.635 0-12 5.365-12 12s5.365 12 12 12c6.926 0 11.52-4.869 11.52-11.726 0-.788-.085-1.39-.189-1.989H12.24z',
+    color: '#4285F4',
+  },
+  {
+    key: 'bing',
+    name: 'Bing',
+    search: 'https://www.bing.com/search?q=',
+    path: 'M5 3v14.895l4.09 2.33v-9.497l6.218 3.535 4.692-2.63-8.724-5.031V3z',
+    color: '#00809D',
+  },
+  {
+    key: 'baidu',
+    name: '百度',
+    search: 'https://www.baidu.com/s?wd=',
+    path: 'M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm0 18c-4.41 0-8-3.59-8-8s3.59-8 8-8 8 3.59 8 8-3.59 8-8 8zm-3-9c-.55 0-1-.45-1-1s.45-1 1-1 1 .45 1 1-.45 1-1 1zm6 0c-.55 0-1-.45-1-1s.45-1 1-1 1 .45 1 1-.45 1-1 1zm-3 6.5c-2.33 0-4.31-1.46-5.11-3.5h10.22c-.8 2.04-2.78 3.5-5.11 3.5z',
+    color: '#2932E1',
+  },
+  {
+    key: 'sogou',
+    name: '搜狗',
+    search: 'https://www.sogou.com/web?query=',
+    path: 'M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm-1.5 14.5c-2.48 0-4.5-2.02-4.5-4.5h2c0 1.38 1.12 2.5 2.5 2.5s2.5-1.12 2.5-2.5h2c0 2.48-2.02 4.5-4.5 4.5zM8 9c.55 0 1 .45 1 1s-.45 1-1 1-1-.45-1-1 .45-1 1-1zm8 0c.55 0 1 .45 1 1s-.45 1-1 1-1-.45-1-1 .45-1 1-1z',
+    color: '#FB6022',
+  },
+  {
+    key: '360',
+    name: '360',
+    search: 'https://www.so.com/s?q=',
+    path: 'M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm0 16c-3.31 0-6-2.69-6-6s2.69-6 6-6 6 2.69 6 6-2.69 6-6 6zm0-9c-1.66 0-3 1.34-3 3s1.34 3 3 3 3-1.34 3-3-1.34-3-3-3z',
+    color: '#19B955',
+  },
 ] as const
 
 type SearchEngine = (typeof SEARCH_ENGINES)[number]
@@ -84,6 +115,16 @@ function readSearchEngine(): SearchEngine {
   }
 }
 
+/** 本地用放大镜；外部引擎用各自的品牌轮廓 */
+function SearchEngineIcon({ engine }: { engine: SearchEngine }) {
+  if (engine.path === '') return <Icon name="search_3_line" />
+  return (
+    <svg viewBox="0 0 24 24" width="18" height="18" aria-hidden="true" focusable="false">
+      <path d={engine.path} fill={engine.color} />
+    </svg>
+  )
+}
+
 function parseRoute(pathname: string): Route {
   const segments = pathname.split('/').filter(Boolean)
   if (segments[0] === 'interface') return { kind: 'api' }
@@ -842,11 +883,11 @@ export default function AppNext() {
               }
               variant="card"
               hotkey="k"
-              suffix={
+              leading={
                 <div className="engine-switch" ref={engineRef}>
                   <button
                     type="button"
-                    className="engine-toggle"
+                    className="engine-trigger"
                     aria-haspopup="menu"
                     aria-expanded={engineOpen}
                     aria-label={`搜索引擎：${searchEngine.name}，点击切换`}
@@ -857,8 +898,7 @@ export default function AppNext() {
                     }
                     onClick={() => setEngineOpen((open) => !open)}
                   >
-                    {searchEngine.name}
-                    <span aria-hidden="true">▾</span>
+                    <SearchEngineIcon engine={searchEngine} />
                   </button>
                   {engineOpen && (
                     <div className="engine-menu" role="menu" aria-label="选择搜索引擎">