chore: update document approval workflow and bug fixes

Modules/ContractorManagement/app/Models/ContractorCertification.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace Modules\ContractorManagement\Models;
+
+use App\Traits\HasPublicIdentifier;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class ContractorCertification extends Model
+{
+    use HasPublicIdentifier;
+
+    protected $fillable = [
+        'contractor_id', 'name', 'certification_number',
+        'issued_date', 'expiry_date', 'status',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'issued_date' => 'date',
+            'expiry_date' => 'date',
+        ];
+    }
+
+    public function contractor(): BelongsTo
+    {
+        return $this->belongsTo(Contractor::class);
+    }
+
+    public function getIsExpiringSoonAttribute(): bool
+    {
+        if (!$this->expiry_date) return false;
+        return $this->expiry_date->isBetween(now(), now()->addDays(30));
+    }
+
+    public function getIsExpiredAttribute(): bool
+    {
+        if (!$this->expiry_date) return false;
+        return $this->expiry_date->isPast();
+    }
+}