Implements Task 7: newTransactionForm and createTransaction controller functions with supporting view.
- Controller generates merTrxId and transCode with UUID-based unique suffix
- Signs transaction using epaySign.signRequest
- Persists AdminTransaction record to MongoDB
- Returns JSON response with code 00/99 and payment URL
- View provides HTML form to submit customer data and display payment link
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>