prmerge-trailer-fixture/mos-poster-plain-message.md

Distinct poster and merge executor control

Non-product fixture for merge-message behavior measurement.

The pull request poster and commit author are mos. The intended merge executor is fred. The proposed measurement supplies a plain, non-trailer-shaped merge title and message through the reviewed merge tooling.

No outcome is asserted before inspecting the resulting commit. Preserve the exact request, source head and resulting commit as evidence. No credentials are shared. Existing review and CI gates remain required.