fix: remove brand name text from mobile flyout header

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/frontend/src/lib/components/header/header.svelte

@@ -190,13 +190,8 @@
   inert={!isMobileMenuOpen || undefined}
 >
   <!-- Panel header -->
-  <div class="flex items-center gap-3 px-5 h-16 shrink-0 border-b border-border/30">
+  <div class="flex items-center px-5 h-16 shrink-0 border-b border-border/30">
     <Logo />
-    <span
-      class="text-xl font-extrabold bg-gradient-to-r from-primary to-accent bg-clip-text text-transparent"
-    >
-      {$_("brand.name")}
-    </span>
   </div>
 
   <div class="flex-1 py-6 px-5 space-y-6">