v1.52.0 — the seat check runs at the release the instance's manifest names

The seat check in the reusable check and in this repository's CI reads the meta-model release from the governing instance's manifest, as the commit-msg hook already did (#117). It ran at v0.89.0, pinned in the workflow, while the hook and each instance's own workflow ran at the instance's release, v0.94.0, and a member on v1.46.0 ran v0.87.0. Now one release checks a member's commits wherever they are checked, and a meta-model release no longer needs a conventions release to reach the seat check. lib/seats.mjs is the same at all three releases, so no verdict moves. The reusable check's marker and the AGENTS.md header name v1.52.0 (#118).

What breaks. Nothing. A governing instance whose manifest names no tooling fails the step instead of running a guessed release; all three instances name one.

How to take it. conventions.json to v1.52.0, the workflow reference check.yml@v1.52.0, and sh conventions/conventions-sync sync. On the owner's word, every member re-syncs to it.

Verified: sh test/run.sh, conventions-check and conventions-format pass on the release commit, and the seat step passed on #117's own pull request at the release robertblust/mental-model's manifest names.