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/components/pages/DashboardPage.js

@@ -1,33 +1,11 @@
 'use client';
 
-/**
- * Admin Dashboard Page
- * Displays core stats and dynamically loads module dashboard widgets
- */
-
-import { Suspense } from 'react';
 import { StatCard } from '../../../../shared/components';
 import { UserMultiple02Icon } from '../../../../shared/Icons.js';
-import { getModuleDashboardWidgets } from '../../../../modules/modules.pages.js';
 
-/**
- * Loading placeholder for widgets
- */
-function WidgetLoading() {
-  return (
-    <div className="animate-pulse bg-neutral-200 dark:bg-neutral-800 rounded-lg h-32"></div>
-  );
-}
-
-export default function DashboardPage({ user, stats, moduleStats = {}, enabledModules = {} }) {
+export default function DashboardPage({ user, stats }) {
   const loading = !stats;
 
-  // Get only enabled module dashboard widgets
-  const allModuleWidgets = getModuleDashboardWidgets();
-  const moduleWidgets = Object.fromEntries(
-    Object.entries(allModuleWidgets).filter(([moduleName]) => enabledModules[moduleName])
-  );
-
   return (
     <div className="flex flex-col gap-4 sm:gap-6 lg:gap-8">
       <div className="flex items-center justify-between">
@@ -40,16 +18,6 @@ export default function DashboardPage({ user, stats, moduleStats = {}, enabledMo
       </div>
 
       <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-4 sm:gap-6">
-        {/* Module dashboard widgets (dynamically loaded) */}
-        {Object.entries(moduleWidgets).map(([moduleName, widgets]) => (
-          widgets.map((Widget, index) => (
-            <Suspense key={`${moduleName}-widget-${index}`} fallback={<WidgetLoading />}>
-              <Widget stats={moduleStats[moduleName]} />
-            </Suspense>
-          ))
-        ))}
-
-        {/* Core stats - always shown */}
         <StatCard
           title="Nombre d'utilisateurs"
           value={loading ? '-' : String(stats?.totalUsers || 0)}