feat: add admin components for input, metrics, tables, and user forms

- Introduced AdminInput component for standardized input fields.
- Created AdminMetricCard for displaying metrics with customizable tones.
- Added AdminPlaceholderTable for loading states in tables.
- Developed AdminSectionCard for consistent section layouts.
- Implemented AdminSectionShell for organizing admin sections.
- Added AdminSelect for dropdown selections with v-model support.
- Created AdminTable for displaying tabular data with loading and empty states.
- Introduced AdminTextarea for multi-line text input.
- Developed AdminUserFormFields for user creation and editing forms.
- Added useAdminPageHeader composable for managing admin page header state.

src/components/DashboardNav.vue

@@ -38,20 +38,6 @@ const links = computed<Record<string, any>>(() => {
     },
     { href: "/settings", label: t("nav.settings"), icon: SettingsIcon, action: null, className },
   ] as const;
-
-  if (isAdmin.value) {
-    return [
-      ...baseLinks,
-      {
-        href: "/admin/overview",
-        label: "Admin Console",
-        icon: LayoutDashboard,
-        action: null,
-        className,
-      } as const,
-    ];
-  }
-
   return baseLinks;
 });
 </script>