fix(workflow): cross-profile decision-lock cleanup and irrecoverable provenance (#709)

Prevent merger-local empty decision locks from standing in for reviewer
terminal cleanup, refuse silent re-init overwrite of unresolved terminal
evidence, record post-merge recovery-required state when audit fails, and
add a truthful irrecoverable-provenance path that never claims applied=true.

Closes #709

mcp_session_state.py

@@ -36,7 +36,21 @@ KIND_REVIEW_DRAFT = "review_draft"
 # other session proofs; a contaminated session fails closed on gated mutations
 # until a reconciler audits and clears it.
 KIND_STABLE_BRANCH_CONTAMINATION = "stable_branch_contamination"
+# #709: archive prior terminal decision ledgers instead of silent overwrite.
+KIND_DECISION_LOCK_ARCHIVE = "review_decision_lock_archive"
+# #709: post-merge cleanup/audit reconciliation-required durable record.
+KIND_POST_MERGE_DECISION_RECOVERY = "post_merge_decision_recovery"
+# #709: truthful record when historical terminal evidence is irrecoverably gone.
+KIND_IRRECOVERABLE_DECISION_PROVENANCE = "irrecoverable_decision_provenance"
 
+# Kinds that must survive the default session-state TTL (forensic / recovery).
+RECOVERY_CRITICAL_KINDS = frozenset(
+    {
+        KIND_DECISION_LOCK_ARCHIVE,
+        KIND_POST_MERGE_DECISION_RECOVERY,
+        KIND_IRRECOVERABLE_DECISION_PROVENANCE,
+    }
+)
 
 
 _SAFE_SEGMENT_RE = re.compile(r"[^A-Za-z0-9._+-]+")
@@ -270,7 +284,11 @@ def identity_match_reasons(
         reasons.append("session state missing recorded_at timestamp (fail closed)")
     else:
         age = _now_utc() - recorded_at
-        if age > timedelta(hours=ttl_hours()):
+        kind = (record.get("kind") or "").strip()
+        ttl_exempt = kind in RECOVERY_CRITICAL_KINDS or bool(
+            record.get("recovery_critical")
+        )
+        if age > timedelta(hours=ttl_hours()) and not ttl_exempt:
             reasons.append(
                 f"session state expired after {ttl_hours():g}h (fail closed)"
             )
@@ -447,3 +465,127 @@ def clear_state(
         profile_identity=profile_identity,
         state_dir=state_dir,
     )
+
+def list_decision_lock_profile_identities(
+    state_dir: str | None = None,
+) -> list[str]:
+    """Return profile identities that have a durable review_decision_lock file (#709).
+
+    Filename form: ``review_decision_lock-<profile>.json`` (see ``state_key``).
+    Does not validate TTL or identity — callers must load via ``load_state``.
+    """
+    root = (state_dir or default_state_dir()).strip()
+    if not root or not os.path.isdir(root):
+        return []
+    prefix = f"{_sanitize_segment(KIND_DECISION_LOCK)}-"
+    suffix = ".json"
+    found: list[str] = []
+    try:
+        names = os.listdir(root)
+    except OSError:
+        return []
+    for name in names:
+        if not name.startswith(prefix) or not name.endswith(suffix):
+            continue
+        if name.endswith(".lock"):
+            continue
+        mid = name[len(prefix) : -len(suffix)]
+        if mid:
+            found.append(mid)
+    return sorted(set(found))
+
+
+def load_state_for_profile(
+    *,
+    kind: str,
+    profile_identity: str,
+    remote: str | None = None,
+    org: str | None = None,
+    repo: str | None = None,
+    state_dir: str | None = None,
+    skip_identity_match: bool = False,
+) -> dict[str, Any] | None:
+    """Load durable state for an explicit profile identity (#709 cross-profile).
+
+    When *skip_identity_match* is True, still requires the file's recorded
+    profile_identity to equal the requested profile (anti-stomp), but does not
+    require the *active* session identity to match — needed so a merger can
+    inspect a reviewer lock after merge.
+    """
+    profile = current_profile_identity(profile_identity=profile_identity)
+    root = _ensure_state_dir(state_dir)
+    path = state_file_path(
+        kind=kind,
+        remote=remote,
+        org=org,
+        repo=repo,
+        profile_identity=profile,
+        state_dir=root,
+    )
+    lock_path = f"{path}.lock"
+    with _exclusive_file_lock(lock_path):
+        envelope = _read_json(path)
+    if not envelope:
+        return None
+    payload = envelope.get("payload")
+    if not isinstance(payload, dict):
+        return None
+    merged = dict(payload)
+    for key in (
+        "kind",
+        "remote",
+        "org",
+        "repo",
+        "profile_identity",
+        "session_profile_lock",
+        "recorded_at",
+        "updated_at",
+        "writer_pid",
+    ):
+        if key in envelope and key not in merged:
+            merged[key] = envelope[key]
+    stored = (merged.get("profile_identity") or "").strip()
+    if stored and stored != profile:
+        return None
+    if skip_identity_match:
+        # Still enforce TTL / future-dated so dead records do not authorize cleanup.
+        reasons = identity_match_reasons(
+            merged,
+            remote=remote or merged.get("remote"),
+            org=org or merged.get("org"),
+            repo=repo or merged.get("repo"),
+            profile_identity=stored or profile,
+        )
+        # Drop active-session-only mismatches; keep expiry / spoof reasons.
+        filtered = [
+            r
+            for r in reasons
+            if "profile identity mismatch" not in r
+            or (stored and stored != profile)
+        ]
+        # Re-run only expiry/future/missing checks via identity when profile matches
+        expiry_reasons = [
+            r
+            for r in identity_match_reasons(
+                merged,
+                remote=None,
+                org=None,
+                repo=None,
+                profile_identity=stored or profile,
+            )
+            if any(x in r for x in ("expired", "future", "missing recorded_at"))
+        ]
+        if expiry_reasons:
+            return None
+        return merged
+    reasons = identity_match_reasons(
+        merged,
+        remote=remote,
+        org=org,
+        repo=repo,
+        profile_identity=profile,
+    )
+    if reasons:
+        return None
+    return merged
+