feat(web): choose where the search sits, and controls no longer select text

- settings get a search position (left, center by default, right); the top bar
  is three zones and the suggestions open towards the free space
- buttons, chips, tabs, menu items and the home screen controls are not
  text-selectable, so clicks and double clicks no longer highlight labels

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/widgets/AppShell.tsx

@@ -93,6 +93,8 @@ function Shell() {
   const name = user.display_name ?? user.username;
   const staff = user.role !== 'user';
   const island = user.ui_prefs.web_player === 'island';
+  const searchAt = user.ui_prefs.search_position ?? 'center';
+  const search = <SearchBox align={searchAt} />;
   const counts = useCollectionCounts();
   const pending = usePendingUploads(user.role === 'admin');
 
@@ -100,11 +102,15 @@ function Shell() {
     <div className={cx(s.shell, island && s.island)}>
       {user.ui_prefs.ambient !== false && <ShellAmbient />}
       <header className={s.top}>
-        <Link to="/" className={s.logoLink}>
-          <Logo />
-        </Link>
+        <div className={s.topLeft}>
+          <Link to="/" className={s.logoLink}>
+            <Logo />
+          </Link>
+          {searchAt === 'left' && search}
+        </div>
+        <div className={s.topCenter}>{searchAt === 'center' && search}</div>
         <div className={s.topRight}>
-          <SearchBox />
+          {searchAt === 'right' && search}
           <Menu
             label={t('profile.menu')}
             triggerClassName={s.profileButton}