Evaluate ct_prop() for migration to generic requests

[seanthimons]

Context

Inline TODO at R/ct_prop.R:1 — evaluate whether ct_prop() can be migrated to generic_request(). May have custom requirements that make migration non-trivial.

Tasks

• Review current ct_prop() implementation for migration feasibility
• Identify any blockers or special handling needed
• Migrate if feasible, or document why not