feat: restructure admin sidebar with collapsible sub-navigation and new routes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/components/layout/AppSidebar.module.css

@@ -209,6 +209,44 @@
   text-align: center;
 }
 
+/* ─── Admin Sub-Menu ─── */
+.adminChevron {
+  margin-left: 6px;
+  font-size: 8px;
+  color: var(--text-muted);
+}
+
+.adminSubMenu {
+  display: flex;
+  flex-direction: column;
+}
+
+.adminSubItem {
+  display: block;
+  padding: 6px 16px 6px 42px;
+  font-size: 12px;
+  color: var(--text-muted);
+  text-decoration: none;
+  transition: all 0.1s;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.adminSubItem:hover {
+  background: var(--bg-hover);
+  color: var(--text-primary);
+}
+
+.adminSubItemActive {
+  color: var(--amber);
+  background: var(--amber-glow);
+}
+
+.sidebarCollapsed .adminSubMenu {
+  display: none;
+}
+
 /* ─── Responsive ─── */
 @media (max-width: 1024px) {
   .sidebar {
@@ -242,4 +280,8 @@
   .sidebar .bottomLabel {
     display: none;
   }
+
+  .sidebar .adminSubMenu {
+    display: none;
+  }
 }

ui/src/components/layout/AppSidebar.tsx

@@ -1,5 +1,5 @@
 import { useMemo, useState } from 'react';
-import { NavLink, useParams } from 'react-router';
+import { NavLink, useParams, useLocation } from 'react-router';
 import { useAgents } from '../../api/queries/agents';
 import { useAuthStore } from '../../auth/auth-store';
 import type { AgentInstance } from '../../api/types';
@@ -112,18 +112,73 @@ export function AppSidebar({ collapsed }: AppSidebarProps) {
       {/* Bottom: Admin */}
       {roles.includes('ADMIN') && (
         <div className={styles.bottom}>
-          <NavLink
-            to="/admin/oidc"
-            className={({ isActive }) =>
-              `${styles.bottomItem} ${isActive ? styles.bottomItemActive : ''}`
-            }
-            title="Admin"
-          >
-            <span className={styles.bottomIcon}>&#9881;</span>
-            <span className={styles.bottomLabel}>Admin</span>
-          </NavLink>
+          <AdminSubMenu collapsed={collapsed} />
         </div>
       )}
     </aside>
   );
 }
+
+const ADMIN_LINKS = [
+  { to: '/admin/database', label: 'Database' },
+  { to: '/admin/opensearch', label: 'OpenSearch' },
+  { to: '/admin/audit', label: 'Audit Log' },
+  { to: '/admin/oidc', label: 'OIDC' },
+];
+
+function AdminSubMenu({ collapsed: sidebarCollapsed }: { collapsed: boolean }) {
+  const location = useLocation();
+  const isAdminActive = location.pathname.startsWith('/admin');
+
+  const [open, setOpen] = useState(() => {
+    try {
+      return localStorage.getItem('cameleer-admin-sidebar-open') === 'true';
+    } catch {
+      return false;
+    }
+  });
+
+  function toggle() {
+    const next = !open;
+    setOpen(next);
+    try {
+      localStorage.setItem('cameleer-admin-sidebar-open', String(next));
+    } catch { /* ignore */ }
+  }
+
+  return (
+    <>
+      <button
+        type="button"
+        className={`${styles.bottomItem} ${isAdminActive ? styles.bottomItemActive : ''}`}
+        onClick={toggle}
+        title="Admin"
+      >
+        <span className={styles.bottomIcon}>&#9881;</span>
+        <span className={styles.bottomLabel}>
+          Admin
+          {!sidebarCollapsed && (
+            <span className={styles.adminChevron}>
+              {open ? '\u25BC' : '\u25B6'}
+            </span>
+          )}
+        </span>
+      </button>
+      {open && !sidebarCollapsed && (
+        <div className={styles.adminSubMenu}>
+          {ADMIN_LINKS.map((link) => (
+            <NavLink
+              key={link.to}
+              to={link.to}
+              className={({ isActive }) =>
+                `${styles.adminSubItem} ${isActive ? styles.adminSubItemActive : ''}`
+              }
+            >
+              {link.label}
+            </NavLink>
+          ))}
+        </div>
+      )}
+    </>
+  );
+}