Create Sandbox Mode API Behavior

[innovativedesign-lab]

Close: #104

Description

1. **Added a database migration file 20260630_add_sandbox_mode.sql to add is_sandbox columns to both the api_keys and transactions tables.
2. Updated src/auth/apikeys.ts to add an isSandbox property to the ApiKey interface and CreateApiKeyOptions .
3. Updated src/middleware/auth.ts to fetch the is_sandbox flag from api_keys table and attach it to the request object.
4. Created a new sandbox service in src/services/sandbox/sandboxService.ts that:
   • Maps phone numbers to specific outcomes (success, insufficient funds, timeout).
   • Provides functions to simulate both mobile money and Stellar payments.
5. Updated src/models/transaction.ts 's TRANSACTION_SELECT_COLUMNS , mapTransactionRow , and create to support isSandbox .
6. Updated src/controllers/transactionController.ts 's processTransactionRequest function to pass isSandbox to TransactionModel.create and to use it.
7. Updated src/queue/worker.ts to use the sandbox service when the transaction is marked as a sandbox transaction.
   All tasks are done! The sandbox mode is now implemented!

Related Issue

Fixes #104

Type of Change

• Bug fix
• New feature
• Documentation update
• Code refactoring
• Performance improvement

Changes Made

Testing

How did you test these changes?

Checklist

• Code follows project style
• Self-reviewed my code
• Commented complex code
• Updated documentation
• No new warnings
• Added tests (if applicable)

Screenshots (if applicable)

Additional Notes

[drips-wave]

@innovativedesign-lab Great news! 🎉 Based on an automated assessment of this PR, the linked Wave issue(s) no longer count against your application limits.

You can now already apply to more issues while waiting for a review of this PR. Keep up the great work! 🚀

Learn more about application limits