chore: update document approval workflow and bug fixes

Modules/ContractorManagement/app/Models/ContractorPayment.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace Modules\ContractorManagement\Models;
+
+use App\Traits\HasPublicIdentifier;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class ContractorPayment extends Model
+{
+    use HasPublicIdentifier;
+
+    protected $fillable = [
+        'contractor_invoice_id', 'amount', 'payment_method',
+        'reference_number', 'notes', 'payment_date',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'amount' => 'decimal:2',
+            'payment_date' => 'date',
+        ];
+    }
+
+    public function invoice(): BelongsTo
+    {
+        return $this->belongsTo(ContractorInvoice::class, 'contractor_invoice_id');
+    }
+}