docs: name the release note after the PR

towncrier fragments are keyed by PR number and use the `feat` type.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KAdFWr2Fo9HAtSiSWF4KPU

Author: alejandro-publius