🚧 Refactor the UI menu

frontend/src/App.tsx

@@ -6,6 +6,63 @@ import { RolesPage } from "./pages/Roles";
 import { GroupsPage } from "./pages/Groups";
 import { BrokerConfigPage } from "./pages/BrokerConfig";
 
+// Navigation structure per spec section 57. Entries with a `to` route are
+// implemented; entries without one are planned pages, rendered greyed out
+// so the full target information architecture stays visible.
+const NAV_SECTIONS: {
+  title: string;
+  items: { label: string; to?: string; hint?: string }[];
+}[] = [
+  {
+    title: "Broker",
+    items: [
+      { label: "Status", hint: "Dashboard / $SYS monitoring (Release 3)" },
+      { label: "Configuration", to: "/broker" },
+      { label: "Listeners", to: "/broker#listeners" },
+      { label: "Bridges", hint: "Bridge management (post-MVP)" },
+      { label: "Revisions", to: "/broker#revisions" },
+    ],
+  },
+  {
+    title: "MQTT Security",
+    items: [
+      { label: "Clients", to: "/clients" },
+      { label: "Groups", to: "/groups" },
+      { label: "Roles", to: "/roles" },
+      { label: "ACL Simulator", hint: "ACL simulator (post-MVP)" },
+      { label: "Authentication", hint: "Auth mechanism configuration (Release 2)" },
+    ],
+  },
+  {
+    title: "Certificates",
+    items: [
+      { label: "Authorities", hint: "PKI (Release 2)" },
+      { label: "Server Certificates", hint: "PKI (Release 2)" },
+      { label: "Client Certificates", hint: "PKI (Release 2)" },
+      { label: "CSRs", hint: "CSR signing (Release 2)" },
+      { label: "Revocations", hint: "CRL management (Release 2)" },
+    ],
+  },
+  {
+    title: "Tools",
+    items: [
+      { label: "Topic Explorer", hint: "Test console (post-MVP)" },
+      { label: "Connection Test", hint: "Connectivity tester (post-MVP)" },
+      { label: "Client Provisioning", hint: "Provisioning wizard (post-MVP)" },
+    ],
+  },
+  {
+    title: "Administration",
+    items: [
+      { label: "Users", hint: "User management page (Release 3)" },
+      { label: "Roles", hint: "Management roles admin (Release 3)" },
+      { label: "Audit Log", hint: "Audit viewer (Release 3)" },
+      { label: "Backup", hint: "Backup/restore (Release 3)" },
+      { label: "System", hint: "System settings (Release 3)" },
+    ],
+  },
+];
+
 function Layout({ children }: { children: React.ReactNode }) {
   const { session, logout } = useAuth();
   return (
@@ -13,10 +70,27 @@ function Layout({ children }: { children: React.ReactNode }) {
       <aside className="sidebar">
         <h1>MQTT Management</h1>
         <nav>
-          <NavLink to="/clients">Clients</NavLink>
-          <NavLink to="/groups">Groups</NavLink>
-          <NavLink to="/roles">Roles &amp; ACLs</NavLink>
-          <NavLink to="/broker">Broker configuration</NavLink>
+          {NAV_SECTIONS.map((section) => (
+            <div key={section.title} className="nav-section">
+              <h2>{section.title}</h2>
+              {section.items.map((item) =>
+                item.to ? (
+                  <NavLink key={item.label} to={item.to}>
+                    {item.label}
+                  </NavLink>
+                ) : (
+                  <button
+                    key={item.label}
+                    className="nav-disabled"
+                    disabled
+                    title={item.hint}
+                  >
+                    {item.label}
+                  </button>
+                ),
+              )}
+            </div>
+          ))}
         </nav>
         <p style={{ marginTop: "2rem", fontSize: "0.8rem", opacity: 0.7 }}>
           {session?.username} ({session?.role})

frontend/src/pages/BrokerConfig.tsx

@@ -113,7 +113,7 @@ export function BrokerConfigPage() {
         <div className="banner error">{(addListener.error as Error).message}</div>
       )}
 
-      <h3 style={{ marginTop: "2rem" }}>Listeners</h3>
+      <h3 id="listeners" style={{ marginTop: "2rem" }}>Listeners</h3>
       <table>
         <thead>
           <tr>
@@ -231,7 +231,7 @@ export function BrokerConfigPage() {
         <div className="banner error">{(deploy.error as Error).message}</div>
       )}
 
-      <h3 style={{ marginTop: "2rem" }}>Revisions</h3>
+      <h3 id="revisions" style={{ marginTop: "2rem" }}>Revisions</h3>
       <table>
         <thead>
           <tr>

frontend/src/styles.css

@@ -39,6 +39,40 @@ body {
   text-decoration: none;
 }
 
+/* --- Grouped navigation (spec section 57) --- */
+.nav-section {
+  margin-bottom: 0.9rem;
+}
+
+.nav-section h2 {
+  font-size: 0.68rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.07em;
+  color: #7b8794;
+  margin: 0.5rem 0 0.25rem;
+  padding-left: 0.6rem;
+}
+
+/* Unimplemented pages: greyed out, not clickable, tooltip explains why. */
+.nav-section button.nav-disabled {
+  display: block;
+  width: 100%;
+  text-align: left;
+  background: transparent;
+  border: none;
+  color: #616e7c;
+  padding: 0.45rem 0.6rem;
+  margin: 0.1rem 0;
+  border-radius: 6px;
+  opacity: 0.55;
+}
+
+/* Anchor targets inside pages: keep headings clear of the viewport top. */
+h3[id] {
+  scroll-margin-top: 1rem;
+}
+
 .sidebar nav a.active,
 .sidebar nav a:hover {
   background: #323f4b;