[BUG] Role request decision endpoint throws 500 due to wrong field name

[vaa-nick-swann]

Summary

Approving/denying a role access request via POST /settings/roles/handle-request returns 500 with an internal error toast.

Repro

1. Submit a role access request.
2. As admin, handle request from Settings.
3. Observe failure toast: internal error during request decision.

Root Cause

In src/backend/src/routes/settings_routes.py, audit logging references:

• request_data.user_email

But HandleRoleRequest model defines:

• requester_email (src/backend/src/models/settings.py)

This triggers an AttributeError, falls into the generic exception handler, and returns 500.

Expected

Role request decision endpoint should complete successfully and return 200.

Actual

500 error: "Failed to process role request decision due to an internal error."

Suggested Fix

Replace request_data.user_email with request_data.requester_email in:

• src/backend/src/routes/settings_routes.py

Also add/adjust test coverage for this route to validate field usage.