fix: resolve conflicts for PR #422

skills/llm-project-workflow/workflows/review-merge-pr.md

@@ -606,6 +606,28 @@ If the cause is unknown, do not erase the earlier failure with plain
 `gitea_validate_review_final_report` rejects reports that omit known earlier
 validation failures when `validation_session.observed_failures` is supplied.
 
+## 21B. Validation status taxonomy (#406)
+
+When the final report summarizes how validation concluded, use one of these
+**validation status** labels (distinct from per-command pass/fail entries):
+
+* `passed` — raw PR-head validation passed on the unmodified head.
+* `failed` — raw PR-head validation failed and no allowed resolution path
+  was proven.
+* `baseline-equivalent failure accepted` — only when a clean baseline
+  worktree under `branches/` proves matching failure signatures on the target
+  branch (baseline path, target SHA, exact commands, failure lists, and
+  `failure signatures match: true`).
+* `raw-head failure resolved by merge simulation` — raw PR-head validation
+  failed, but merge simulation into the current target passed cleanly; report
+  merge simulation under `Worktree/index mutations` with full #317 proof.
+* `passed after transient failure investigation` — a later run passed after an
+  earlier failure in the same session; document the failure history (#396).
+
+Do not use `baseline-equivalent failure accepted` when only merge simulation
+resolved the failure. Do not use bare `passed` when raw PR-head validation
+failed unless one of the resolution statuses above applies.
+
 ## 22. Baseline validation rule
 
 Do not run tests in the main checkout.
@@ -790,6 +812,24 @@ inventory before continuing.
 Final reports must include lease session id, acquisition proof, heartbeat
 status, and release/blocked status.
 
+## 26C. Conflict-fix lease and stale-head protection (#399)
+
+Before validating, approving, or merging a PR:
+
+1. Check for an active conflict-fix lease on the PR; stop if one is active.
+2. Pin `expected_head_sha` before validation and pass it to
+   `gitea_mark_final_review_decision`, `gitea_submit_pr_review`, and
+   `gitea_merge_pr`.
+3. Re-fetch live PR head immediately before approval and merge; refuse when
+   live head differs from the reviewed SHA.
+
+Final reports must state:
+
+* reviewed head SHA
+* final live head SHA before approval
+* final live head SHA before merge
+* whether any push occurred during validation
+
 ## 27. Merge rules
 
 Before merge, rerun fresh live checks:
@@ -800,6 +840,7 @@ Before merge, rerun fresh live checks:
 * author safety
 * PR re-fetch
 * reviewed head SHA unchanged
+* visible APPROVED review applies to the **current live PR head SHA** (`approval_at_current_head`); if the head moved after approval, re-review at the new head before merge (#471)
 * target branch freshly fetched
 * PR still open
 * PR still mergeable
@@ -816,6 +857,7 @@ Do not merge if:
 * capability state is stale
 * worktree is dirty
 * PR head changed
+* approval is stale (approved SHA ≠ current live head SHA)
 * validation failed
 * inventory was incomplete
 * PR is already landed