refactor: remove module system integration from admin and CLI

Removes all module-related logic from the admin dashboard, CLI database
initialization, and AdminPages component:

- Drop `initModules` call from `db init` CLI command and simplify the
  completion message to only reflect core feature tables
- Remove `getModuleDashboardStats` and module page routing from admin
  stats actions and update usage documentation accordingly
- Simplify `AdminPagesClient` to remove module page loading, lazy
  components, and module-specific props (`moduleStats`, `modulePageInfo`,
  `routeInfo`, `enabledModules`)

src/features/admin/page.js

@@ -12,41 +12,6 @@ import { getDashboardStats } from '@zen/core/admin/actions';
 import { logoutAction } from '@zen/core/auth/actions';
 import { getAppName } from '@zen/core';
 
-function parseAdminRoute(params) {
-  const parts = params?.admin || [];
-
-  if (parts.length === 0) {
-    return { path: '/admin/dashboard', action: null, id: null };
-  }
-
-  const corePages = ['dashboard', 'users', 'profile'];
-  if (corePages.includes(parts[0])) {
-    if (parts[0] === 'users' && parts[1] === 'edit' && parts[2]) {
-      return { path: '/admin/users', action: 'edit', id: parts[2] };
-    }
-    return { path: `/admin/${parts[0]}`, action: null, id: null };
-  }
-
-  let pathParts = [];
-  let action = null;
-  let id = null;
-  const actionKeywords = ['new', 'create', 'edit'];
-
-  for (let i = 0; i < parts.length; i++) {
-    const part = parts[i];
-    if (actionKeywords.includes(part)) {
-      action = part === 'create' ? 'new' : part;
-      if (action === 'edit' && i + 1 < parts.length) {
-        id = parts[i + 1];
-      }
-      break;
-    }
-    pathParts.push(part);
-  }
-
-  return { path: '/admin/' + pathParts.join('/') + (action ? '/' + action : ''), action, id };
-}
-
 export default async function AdminPage({ params }) {
   const resolvedParams = await params;
   const session = await protectAdmin();
@@ -56,7 +21,6 @@ export default async function AdminPage({ params }) {
   const dashboardStats = statsResult.success ? statsResult.stats : null;
 
   const navigationSections = buildNavigationSections('/');
-  const { path, action, id } = parseAdminRoute(resolvedParams);
 
   return (
     <AdminPagesLayout
@@ -69,7 +33,6 @@ export default async function AdminPage({ params }) {
         params={resolvedParams}
         user={session.user}
         dashboardStats={dashboardStats}
-        routeInfo={{ path, action, id }}
       />
     </AdminPagesLayout>
   );