Custom edit invoice price for a subscription order

🔍 Problem Statement

Admins cannot manually edit the invoice price for a subscription order. When custom pricing agreements exist or adjustments are needed, there is no way to override the system-calculated amount — forcing workarounds through credits or separate invoices.

💡 User Story

As a Pelcro admin, I want to manually edit the invoice price for a subscription order, so that I can apply custom pricing or adjustments directly without creating workarounds.

🎯 Definition of Done (DoD)

A feature is done when:

✔️ Given a subscription order, when an admin edits the invoice price and saves, then the updated amount is reflected on the invoice, correctly recorded in accounting, and the original system-calculated amount is preserved for audit.