release: v0.28.6 — TP-186 worker death-spiral fix (#537, #542)

[HenryLach]

Release v0.28.6

Single P0 bug fix: the worker death-spiral that made Review Level ≥ 2 unsafe in production.

Fixed

• TP-186 / Worker spins indefinitely when code review returns REVISE on a step already marked complete in STATUS #537 / Worker pattern: premature step-completion in STATUS before final review APPROVE #542 — Worker death-spiral when code review returns REVISE on a step already marked Complete in STATUS. Adds explicit Order of Operations rule + Recovery Recipe + Forbidden callout to templates/agents/task-worker.md (Option A, preventive). Adds isStepMarkedComplete() helper + guard in agent-bridge-extension.ts that refuses review_step(type='code'|'test') on already-complete steps with REFUSED + recovery instructions (Option B, defensive). Plan reviews are NOT blocked. Supersedes Lane-runner should enforce STATUS.md checkpoint discipline at step boundaries #510 (earlier partial diagnosis). Sage-reviewed.

Validation

• ✅ Tests: 3467 passing / 0 failed / 1 skipped (was 3452 baseline + 15 new)
• ✅ Plan + code reviews fired during the implementation batch — both APPROVED
• ✅ Sage independent review — primary fix confidence High; folded in 2 follow-ups (REFUSED in Handling verdicts; markdown emphasis typo) before merge
• ✅ CLI smokes clean
• ✅ Worker writing the fix completed without triggering the bug being fixed (recursive self-consistency check)

Test count growth

• v0.28.5: 3452 passing
• v0.28.6: 3467 passing (+15 from worker-step-completion-protocol.test.ts)

Tag

v0.28.6 will be pushed AFTER this PR merges (so the release workflow's tag-push trigger fires against a commit already on main). Use --merge (not squash) when merging this PR so the version-bump commit is preserved in main's linear history for npm view taskplane time and gh release view v0.28.6.

Closes

This release ships:

• Closes Worker spins indefinitely when code review returns REVISE on a step already marked complete in STATUS #537 (already closed by PR fix(TP-186): worker death-spiral via explicit step-completion protocol (#537, #542) #547 merge)
• Closes Worker pattern: premature step-completion in STATUS before final review APPROVE #542 (already closed by PR fix(TP-186): worker death-spiral via explicit step-completion protocol (#537, #542) #547 merge)
• Closes Lane-runner should enforce STATUS.md checkpoint discipline at step boundaries #510 (manually closed; superseded by fix(TP-186): worker death-spiral via explicit step-completion protocol (#537, #542) #547)

Post-merge sequence

1. Merge with --merge (preserves the tagged commit)
2. Sync local main: git switch main && git pull --ff-only
3. Push tag: git push origin v0.28.6 — this triggers the release workflow
4. Workflow auto-publishes to npm with provenance + creates GitHub release

Deferred (TP-189 candidates)

Sage-flagged polish items intentionally not blocking this release:

• Reconcile older-prompt ambiguity about checkbox-done vs. step-transition vs. the new rule
• Runtime refusal test for the guard's execution path (mock spawn, assert no reviewer + no counter increment)
• Fenced-code-block filter in isStepMarkedComplete (edge case)
• TP-187 + TP-188 from the same emailgistics-astro postmortem (recovery UX + reviewer typecheck + Windows worktree fallback)