Don't let user pay twice for the same NOI

**Jira Ticket**: ALCS-2519

**Description**: If we put the link to pay in the email, that means the agent could forward the email to other people. We dont want two people paying for the same file twice, so dont let them pay if we have already received the payment.

*Acceptance Criteria*
* dont let user pay for the same NOI twice

Figma: [https://www.figma.com/design/b9CR3LfjANgDbnqRif23VM/ALC-Portal?node-id=2336-16981&t=C61dZbIE2v8WhdEO-4] 

**Last Updated**: 2025-03-18 10:00

Start by tracing the NOI payment flow and how the existing email link identifies the file and records payment; the issue names no source files or tests, so locate those entry points first. Reproduce two payment attempts for the same NOI, then verify that a second attempt is blocked after the first payment has been received, including when the email is forwarded.

Written by the indexing model from the issue text.