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/Models/UserConsent.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+/**
+ * Immutable audit record of a user consent event.
+ *
+ * Captures which legal document version was accepted, when, from which IP
+ * and through which channel, enabling full LGPD accountability.
+ */
+#[Fillable(['user_id', 'legal_document_id', 'accepted_at', 'ip_address', 'user_agent', 'source'])]
+class UserConsent extends Model
+{
+    /**
+     * Attributes that should be cast to native types.
+     *
+     * @return array<string, string>
+     */
+    protected function casts(): array
+    {
+        return [
+            'accepted_at' => 'datetime',
+        ];
+    }
+
+    /**
+     * User that granted the consent.
+     *
+     * @return BelongsTo<User, $this>
+     */
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    /**
+     * Legal document version that was accepted.
+     *
+     * @return BelongsTo<LegalDocument, $this>
+     */
+    public function document(): BelongsTo
+    {
+        return $this->belongsTo(LegalDocument::class, 'legal_document_id');
+    }
+}