feat: add City10 platform with Laravel 13, AI agents, 3D viewer, and LGPD compliance

Initial commit of the complete City10 virtual city simulation platform.

Backend (Laravel 13):
- REST API with Sanctum tokens and session-based web authentication
- Role-based access control (admin/user) with middleware protection
- AI agent CRUD with OpenRouter.ai integration restricted to free models
- Store management with 3D coordinates and AI shopkeeper assignment
- Versioned legal documents (Terms, Privacy, Cookies) with LGPD audit trail
- Math CAPTCHA on public forms and multi-language support (pt_BR, en, es)

Frontend:
- Responsive Blade templates with Tailwind CSS v4
- Three.js 3D city viewer with SSE chat streaming to AI agents
- Admin panel for store and user administration

Infrastructure:
- MariaDB/MySQL database with comprehensive migrations
- Database seeders for demo content and test accounts
- PHPUnit test suite and Laravel Pint code styling
- Vite build configuration with hot reload

app/Http/Requests/Traits/ValidatesMathCaptcha.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace App\Http\Requests\Traits;
+
+use Illuminate\Support\Facades\Session;
+
+/**
+ * Simple arithmetic CAPTCHA implemented with pure Laravel primitives.
+ *
+ * Generates a sum of two random integers, stores the expected result in
+ * the session and validates the user answer. It introduces no external
+ * dependency and is therefore safe from third-party licensing concerns.
+ */
+trait ValidatesMathCaptcha
+{
+    /**
+     * Generate a new math challenge and persist it in the session.
+     *
+     * @return array{a: int, b: int, question: string}
+     */
+    protected static function generateMathCaptcha(): array
+    {
+        $a = random_int(1, 9);
+        $b = random_int(1, 9);
+
+        Session::put('captcha_result', $a + $b);
+        // Sliding expiry: challenge is valid for 10 minutes.
+        Session::put('captcha_expires_at', now()->addMinutes(10)->getTimestamp());
+
+        return [
+            'a' => $a,
+            'b' => $b,
+            'question' => sprintf('%d + %d = ?', $a, $b),
+        ];
+    }
+
+    /**
+     * Validate the submitted CAPTCHA answer against the session value.
+     */
+    protected function validateMathCaptcha(): bool
+    {
+        $expected = Session::get('captcha_result');
+        $expiresAt = Session::get('captcha_expires_at');
+
+        // Invalidate the challenge after it is consumed.
+        Session::forget(['captcha_result', 'captcha_expires_at']);
+
+        if ($expected === null || $expiresAt === null) {
+            return false;
+        }
+
+        if (now()->getTimestamp() > (int) $expiresAt) {
+            return false;
+        }
+
+        return (int) $this->input('captcha') === (int) $expected;
+    }
+}