feat: L'Ami Fiduciaire V1.0.0 — full codebase with Story 0.1 complete

Initial commit of the L'Ami Fiduciaire SaaS platform built on Laravel 12,
Vue 3, Inertia.js 2, and Tailwind CSS 4.

Story 0.1 (rename folders to declarations in database) is implemented and
code-reviewed: migration, rollback, and 6 Pest tests all passing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Http/Middleware/EnsureUserIsAdmin.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use App\Enums\UserGroup;
+use Closure;
+use Illuminate\Http\Request;
+use Symfony\Component\HttpFoundation\Response;
+
+class EnsureUserIsAdmin
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  \Closure(\Illuminate\Http\Request): (\Symfony\Component\HttpFoundation\Response)  $next
+     */
+    public function handle(Request $request, Closure $next): Response
+    {
+        $user = $request->user();
+
+        if (! $user || (! $user->group->is(UserGroup::Admin) && ! $user->group->is(UserGroup::Superadmin))) {
+            abort(403);
+        }
+
+        return $next($request);
+    }
+}