[Merged] Make Orders Available to be Paid via Invoice

[Merged into Support additional payment methods for e-commerce orders (Invoice, PayPal, Google Pay, Apple Pay)]

🔍 Problem Statement

Orders (e-commerce) can only be paid via immediate card charge. There is no option to generate an invoice for an order, which blocks clients who need invoice-based payment workflows for their e-commerce products.

💡 User Story

As a Pelcro admin, I want orders to be payable via invoice, so that customers who prefer or require invoice-based billing can complete purchases without immediate card payment.

🎯 Definition of Done (DoD)

A feature is done when:

✔️ Given an order, when an admin selects invoice as the payment method, then an invoice is generated for the order amount and sent to the customer — and the order is fulfilled upon payment.