feat: add Devis and BesoinInformatique modules

- Devis: CRUD complet, génération PDF (dompdf), paramètres (DevisSetting)
- BesoinInformatique: CRUD complet avec gestion matériels/licences
- Migrations pour les 3 nouvelles tables
- Navigation mise à jour dans AuthenticatedLayout

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

app/Models/Devis.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+
+class Devis extends Model
+{
+    protected $guarded = [];
+
+    protected $casts = [
+        'items' => 'array',
+        'date_devis' => 'date',
+        'total_ht' => 'decimal:2',
+        'total_ttc' => 'decimal:2',
+        'tva_rate' => 'decimal:2',
+    ];
+
+    protected static function booted()
+    {
+        static::creating(function ($devis) {
+            if (empty($devis->number)) {
+                $year = date('Y');
+                $prefix = sprintf('DEV-%s-', $year);
+                $last = static::where('number', 'like', $prefix . '%')
+                    ->max('number');
+                $next = $last ? (intval(substr($last, strlen($prefix))) + 1) : 1;
+                $devis->number = $prefix . sprintf('%04d', $next);
+            }
+        });
+    }
+}