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/HandleAppearance.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+use Illuminate\Http\Request;
+use Illuminate\Support\Facades\View;
+use Symfony\Component\HttpFoundation\Response;
+
+class HandleAppearance
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  Closure(Request): (Response)  $next
+     */
+    public function handle(Request $request, Closure $next): Response
+    {
+        View::share('appearance', $request->cookie('appearance') ?? 'system');
+
+        return $next($request);
+    }
+}