feat(fe): remove Settings page from dashboard

Hapus halaman /settings + nav item Settings (TopNav/HiddenSidebar
via navItems). GlassDivider ikut dihapus (cuma dipakai settings).
useConfig tetap (dipakai guild-selector).

Verifikasi: tsc PASS, biome 0 error, next build PASS (10 halaman
static, settings hilang).

services/frontend/src/lib/navigation.ts

@@ -6,7 +6,6 @@ import {
   Mic,
   Music,
   Search,
-  Settings,
 } from "lucide-react";
 
 export interface NavItem {
@@ -57,12 +56,6 @@ export const navItems: NavItem[] = [
     icon: Search,
     matchPrefix: "/analysis",
   },
-  {
-    href: "/settings",
-    label: "Settings",
-    icon: Settings,
-    matchPrefix: "/settings",
-  },
 ];
 
 /**