feat(migrations): add phone number field migration for client model

A new migration file has been created to modify the client model's phone field.

**New Features**
- Added migration `0005_alter_client_phone.py` to alter the client phone field using `phonenumber_field`

**Enhancements & Refinements**
- Updated client phone field to use `PhoneNumberField` with extended length support and region flexibility

src/migrations/0005_alter_client_phone.py

@@ -0,0 +1,21 @@
+# Generated by Django 6.0 on 2025-12-14 04:18
+
+import phonenumber_field.modelfields
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("src", "0004_alter_invoice_due_date"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="client",
+            name="phone",
+            field=phonenumber_field.modelfields.PhoneNumberField(
+                max_length=128, region=None
+            ),
+        ),
+    ]