The frozen entry-point bodies of five merge-pr scripts are removed #883

Problem

After child 20 nothing reaches the frozen bodies of five merge-pr scripts: lint-squash-msg.sh, populate-description.sh, squash-message.sh, review.sh and preflight.sh. They hold 515 code lines in packages/agents/source/skills/merge-pr/shared/scripts/ (25, 62, 156, 108 and 164), and the merge path no longer needs them.

This child removes only non-owner shell. merge-agent.sh and merge-policy.py match owner_paths and constitutional_paths in .agents/agent-skills.conf at origin/main, so deleting them (with their generated copies) belongs to the single cutover issue under #588, which depends on this child. They are unreachable after child 20 and stay in place until then.

Part of #324, within #588. Child 22 in #324's Children list. Removes the frozen bodies of the five scripts and their generated copies.

Acceptance criteria

1. AC1: Given the sources, packages and deployments, when a search for the frozen bodies of the five scripts runs after this change, then none remains in the source, both harness packages and both deployments; the wrappers of children 14 and 27 still exist and work.
2. AC2: Given the complete regeneration sequence of mise.toml (regen-generated, followed by check-generated-skills), when it runs, then output is current, tokens.json is re-measured, the deployments and apm.lock.yaml are refreshed and the check passes.
3. AC3: Given the documentation, when it mentions the removed bodies or the fallback they served, then it is updated, and a reference search over the documentation shows no obsolete guidance.
4. AC4: Given the merge path, when CI runs on macOS, Linux and Windows, then it passes with the frozen bodies absent.
5. AC5: Non-functional: no wrapper, Go test or Bats case references a removed body, the only remaining references to the removed files are in merge-agent.sh and merge-policy.py (owner paths, deleted at the cutover), and this change edits no path matched by constitutional_paths or owner_paths in .agents/agent-skills.conf.

Scope and non-goals

Scope: the deletion of the five frozen bodies, regenerated output and documentation.

Non-goal: changing Go behavior. Non-goal: deleting merge-agent.sh, merge-policy.py, lib.sh or any other owner-tier or constitutional path, which the cutover issue under #588 does. Non-goal: squash-merge.sh and pull-request.sh (child 23).

Approach

Meet AC1 to AC5 in one deletion with regenerated output. Mechanism is the implementer's choice.

Dependencies

Blocked by: #882, #876, #333.

The cutover issue under #588 (not a child of this split) follows this child.

Prerequisites: #333.

Size

S. One pull request. 515 code lines deleted from source at origin/main (a physical-line code count), under 800 with documentation. Only generated output under packages/agents/claude/.apm/skills/, packages/agents/codex/.apm/skills/, .claude/skills/, .agents/skills/ and tokens.json is excluded from the count; the source copy always counts.

Verify plan

• AC1: the search output over source, packages and deployments.
• AC2: mise run regen-generated then mise run check-generated-skills, with the tokens, deployments and lock diff cited.
• AC3: the lint-prose and Markdown gates and a documentation reference search.
• AC4: the CI matrix run.
• AC5: a search of the tests for the removed names, and the protected-path scan output on the pull request's file list.
• Definition of done: D1 each AC is verified at the merged head, with the commands and results cited in the pull request's Verification. D2 an independent review approves the exact merged head, and every finding has a recorded disposition. D3 required checks pass with no gate loosened. D4 the leak scans the repository specifies are clean, and every post made for this work passes the per-post leak review before it is posted. D5 every commit is signed. D6 the documentation matches the change or the Verification says why there is no impact. D7 every commit has an Assisted-by trailer and the pull request has the provenance:agent-assisted label. D8 the pull request stays within the size limits. D9 follow-ups are filed as issues and listed under Related. D10 the merge closes the issue through a closing reference, the board shows Done, and the final Status: comment names the merge commit.

Risks

A leftover caller would fail at run time; AC1 and AC5 search for callers. Undo: revert; the files return.

Operator authority

None. No path matched by constitutional_paths or owner_paths is touched (AC5).