Initial commit: Horux Backend API

- API REST para gestion de facturas electronicas mexicanas (CFDI)
- Laravel 9 con autenticacion OAuth 2.0 (Passport)
- Integracion con Syntage, Clerk y Facturama
- 30 modelos Eloquent, 39 controladores
- Documentacion completa en /docs

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/Models/InvoiceLine.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Model;
+
+class InvoiceLine extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'id'
+    ];
+
+    public function invoice(): BelongsTo
+    {
+        return $this->belongsTo(Invoice::class);
+    }
+
+    public function rfc(): BelongsTo
+    {
+        return $this->belongsTo(Rfc::class);
+    }
+
+    public function invoiceType(): BelongsTo
+    {
+        return $this->belongsTo(InvoiceType::class);
+    }
+
+    public function paymentType(): BelongsTo
+    {
+        return $this->belongsTo(PaymentType::class);
+    }
+
+    public function issuerRfc(): BelongsTo
+    {
+        return $this->belongsTo(Rfc::class);
+    }
+
+    public function receiverRfc(): BelongsTo
+    {
+        return $this->belongsTo(Rfc::class);
+    }
+
+    public function getIssuerRfcAttribute()
+    {
+        return $this->issuerRfc()->first()->rfc;
+    }
+
+    public function getReceiverRfcAttribute()
+    {
+        return $this->receiverRfc()->first()->rfc;
+    }
+
+    protected $keyType = 'string';
+
+    protected $hidden = ['issuer_rfc_id', 'receiver_rfc_id'];
+
+    protected $appends = ['issuer_rfc', 'receiver_rfc'];
+}