feat(ui): [UI7-1] 重构主布局AppShell与导航层

client/src/components/navigation/Sidebar.tsx

@@ -2,13 +2,13 @@ import { NavLinks } from "./NavLinks";
 
 export function Sidebar() {
   return (
-    <aside className="hidden w-64 shrink-0 border-r border-slate-200 bg-white lg:flex lg:flex-col">
-      <div className="border-b border-slate-200 px-6 py-5">
-        <p className="text-sm font-semibold uppercase tracking-wide text-primary">hyb-oa</p>
-        <h1 className="mt-1 text-lg font-bold text-slate-900">海音达工作台</h1>
+    <aside className="hidden w-64 border-r border-zinc-200 bg-white lg:flex lg:flex-col fixed inset-y-0 z-20">
+      <div className="border-b border-zinc-200 p-6 flex items-center gap-3">
+        <div className="size-8 bg-zinc-900 rounded-lg flex items-center justify-center text-white font-bold text-lg">H</div>
+        <span className="font-bold text-zinc-900 tracking-tight">海音达工作台</span>
       </div>
 
-      <div className="flex-1 p-4">
+      <div className="flex-1 p-3">
         <NavLinks />
       </div>
     </aside>