Add support for MTN Mobile Money

Add MTN Mobile Money API Adapter

Description:

We're looking to expand EasySwitch's capabilities by adding support for MTN Mobile Money payments. This will enable developers to seamlessly integrate with one of Africa's largest mobile money platforms through our unified SDK.

Key Integration Points Needed:

• ✅ MTN Mobile Money API authentication
• ✅ Send payment requests
• ✅ Check transaction status
• ✅ Handle webhook notifications
• ✅ Process refunds (where supported)

Expected Behavior:

# Example of ideal usage:
response = await client.send_payment(
    provider="mtn",
    amount=1000,
    phone_number="233541234567",  # MTN Ghana number format example
    currency="GHS",
    reference="order_123"
)

Technical Requirements:

1. Base API URL: https://api.mtn.com/v1/ (sandbox available)
2. Auth: API Key + OAuth2
3. Required endpoints:
   • /collection/request-to-pay
   • /disbursement/transfer
   • /transaction/status

Resources for Contributors:

• MTN API Documentation (Developer Portal)
• Existing Adapter Examples (Orange/Wave implementations)

Contribution Guide:

1. Fork the repository
2. Create new branch: feat/mtn-adapter
3. Implement in easyswitch/adapters/mtn.py
4. Add comprehensive tests
5. Submit PR referencing this issue

This is a great opportunity to:

• Work with real-world payment APIs
• Contribute to a growing open-source project
• Get your work used by developers across Africa

Would you like to take this on? Comment below to claim the issue!

Labels: good first issue, enhancement, help wanted

Start by reading the existing Orange and Wave adapters in easyswitch/adapters and the MTN API documentation. Implement the adapter in easyswitch/adapters/mtn.py, covering authentication, collection, disbursement, status, webhooks, and supported refunds. Add comprehensive tests and verify the example unified client usage.