Accept documented Micro-Delta PR reviews across MCP and CI review-body lint

Context

#13910 originally covered the documented Micro-Delta PR-review template being rejected by the MCP manage_pr_review validator. PR #13911 resolved that MCP surface.

On 2026-06-28, PR #14282 exposed the residual enforcement-surface gap: manage_pr_review accepted a documented # Pull Request Micro-Delta Review, but the GitHub Actions lint-pr-review-body job in .github/workflows/agent-pr-review-body-lint.yml rejected the same review body because the workflow still only recognized the full/follow-up review anchors plus the Micro-Review light path.

This ticket now covers the remaining parity fix: the CI review-body lint surface must accept the same documented Micro-Delta shape as PullRequestService.mjs, without weakening the existing full/follow-up anti-Goodhart validation.

Architectural Reality

The current sources define three relevant review-body validation tiers:

• Full / follow-up PR review bodies: heavy graph-ingestion template checks with visible and invisible anchors.
• Micro-Review bodies: cycle-1 blast-scaled light shape for micro or contained PRs.
• Micro-Delta bodies: cycle-N cost-compression shape for review-loop state (a), where semantics are cleared and only mechanical-hygiene or metadata-drift remains.

ai/services/github-workflow/PullRequestService.mjs already implements all three tiers and has #13910 unit coverage for Micro-Delta pass/fail behavior. The workflow companion still lacks the Micro-Delta tier, so agents using the documented format through a valid review path can still get a red CI lint check.

The workflow runs as inline actions/github-script; it does not currently import repo-local validator helpers. The near-term release fix is therefore to keep the inline workflow constants synchronized with the MCP validator and add focused coverage around the workflow script, not to split a new helper extraction lane.

Contract Ledger Matrix

Acceptance Criteria

• Update .github/workflows/agent-pr-review-body-lint.yml to accept valid # Pull Request Micro-Delta Review bodies using the same required anchors and blocker-class guard as PullRequestService.mjs.
• Reject incomplete Micro-Delta-like bodies before the workflow falls through to the full/follow-up validator.
• Reject Micro-Delta bodies whose Remaining Blocker Class is not mechanical-hygiene or metadata-drift.
• Preserve the existing full/follow-up visible, invisible, and premise-snapshot validation path.
• Keep CI reviewer premise-snapshot enforcement aligned with PullRequestService.mjs, including Premise Coherence, unless a deliberate exception is documented in the PR.
• Add focused unit coverage for the workflow-script behavior or an equivalent extracted workflow validator fixture.

Out of Scope

• Reworking the entire PR-review template system.
• Weakening the anti-Goodhart visible/invisible anchor guard.
• Spawning a separate micro-ticket or micro-PR for this residual CI parity fix.

Avoided Traps

• Do not bypass validation for Micro-Delta reviews wholesale. The bug is that one documented template class is missing from the CI accepted skeletons.
• Do not stuff metric tags into Micro-Delta reviews to satisfy the full/follow-up validator; that recreates the expensive template the circuit breaker is meant to avoid.
• Do not split this into another leaf PR unless the operator explicitly changes direction.

Successor / Duplicate Evidence

• PR #13911 merged on 2026-06-23 and resolved the MCP manage_pr_review portion only.
• PR #14282 on 2026-06-28 reproduced the residual CI lint mismatch on a valid Micro-Delta review.
• Live search for Micro-Delta review-body lint surfaces #13910 as the active implementation ticket; no separate residual-CI ticket is needed.