refactor: 菜单栏角色化降噪（role-based-navigation-simplification）

client/src/index.css

@@ -152,6 +152,28 @@
     color: var(--color-accent-primary);
   }
 
+  .nav-more-section {
+    @apply space-y-1.5;
+  }
+
+  .nav-more-section__summary {
+    color: var(--color-text-secondary);
+    @apply flex cursor-pointer list-none items-center gap-2.5 rounded-lg px-2.5 py-2 text-sm transition duration-150 hover:bg-slate-50 hover:text-slate-950;
+  }
+
+  .nav-more-section__summary::-webkit-details-marker {
+    display: none;
+  }
+
+  .nav-more-section__chevron {
+    color: var(--color-text-tertiary);
+    @apply text-[18px] transition-transform;
+  }
+
+  .nav-more-section[open] .nav-more-section__chevron {
+    transform: rotate(180deg);
+  }
+
   .auth-shell {
     background:
       radial-gradient(circle at 20% 12%, rgba(0, 57, 138, 0.10), transparent 26rem),