feat: add sanctions and velocity compliance checks

[CMI-James]

Description
Added sanctions screening and rolling 24h velocity checks to payments, transfers, and withdrawals so
compliance violations fail fast.

Closes #69

Changes proposed
What were you told to do?

• Build sanctions screening + velocity guard that rejects flagged accounts and over-limit volumes.
• Prevent payments/withdrawals/transfers from progressing if compliance checks fail.
• Track each user’s 24h volume via Redis sorted set and throw 403 when exceeding $1k.

What did I do?

• Implemented parsing amount to stroops, Redis sorted-set maintenance, and total calculation with
  ApiError feedback in server/src/services/compliance.service.ts.
• Hooked compliance guard into payment creation, transfer, and anchor withdrawal flows so userId
  sanctions/velocity are verified before transaction construction.
• Ensured requests surface 403 errors on violations by throwing ApiError and left logging for
  failure reasons.

Check List (Check all the applicable boxes)

• My code follows the code style of this project.
• This PR does not contain plagiarized content.
• The title and description of the PR is clear and explains the approach.
• I am making a pull request against the dev branch (left side).
• My commit messages styles matches our requested structure.
• My code additions will fail neither code linting checks nor unit test.
• I am only making changes to files I was requested to.

[CMI-James]

@anonfedora
kindly review

[CMI-James]

@anonfedora conflict resolved