feat: enforce self-propagating canonical handoffs through controller closure (Closes #626)

Adds the canonical cross-role handoff schema and its fail-closed validator,
live-state recovery, role-limited continuation, mandatory durable posting,
the merged-awaiting-controller boundary, controller accept/reject
continuation, and workflow-failure escalation with duplicate handling.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

final_report_validator.py

@@ -19,6 +19,10 @@ import reviewer_handoff_consistency
 import thread_state_ledger_validator
 from mcp_native_cleanup_proof import assess_mcp_native_cleanup_proof
 from post_merge_cleanup_proof import assess_post_merge_cleanup_proof
+from self_propagating_handoff import (
+    HANDOFF_HEADING as SELF_PROPAGATING_HANDOFF_HEADING,
+    assess_final_report_self_propagating_handoff,
+)
 from review_proofs import (
     HANDOFF_HEADING,
     assess_controller_handoff,
@@ -1623,6 +1627,21 @@ def _rule_shared_mcp_native_cleanup_proof(report_text: str) -> list[dict[str, st
     )
 
 
+def _rule_shared_self_propagating_handoff(report_text: str) -> list[dict[str, str]]:
+    """#626: a report that adopts the handoff protocol must complete it."""
+    result = assess_final_report_self_propagating_handoff(report_text)
+    if not result.get("applicable") or not result.get("block"):
+        return []
+    return _findings_from_reasons(
+        "shared.self_propagating_handoff",
+        result.get("reasons") or ["incomplete canonical handoff"],
+        field=SELF_PROPAGATING_HANDOFF_HEADING,
+        severity="block",
+        safe_next_action=result.get("safe_next_action")
+        or "complete every canonical handoff field before posting",
+    )
+
+
 _SHARED_ISSUE_LOCK_RULES = (
     _rule_shared_issue_lock_external_state,
     _rule_shared_manual_lock_pr_override,
@@ -1647,8 +1666,14 @@ _SHARED_MUTATION_BUDGET_RULES = (
     _rule_shared_mutation_budget_accounting,
 )
 
+# #626: enforced for every task kind that can continue the workflow chain.
+_SHARED_SELF_PROPAGATING_HANDOFF_RULES = (
+    _rule_shared_self_propagating_handoff,
+)
+
 _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
     "review_pr": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1684,6 +1709,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_reviewer_stale_head_proof,
     ],
     "merge_pr": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_email_disclosure,
         *_SHARED_ISSUE_LOCK_RULES,
@@ -1695,6 +1721,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_reviewer_stale_head_proof,
     ],
     "reconcile_already_landed": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_reconcile_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1715,6 +1742,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_audit_reconciliation_boundary,
     ],
     "author_issue": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1725,6 +1753,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_reviewer_vague_mutations_none,
     ],
     "work_issue": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1739,6 +1768,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_worktree_cleanup_audit_proof,
     ],
     "issue_filing": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1748,6 +1778,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         *_SHARED_ISSUE_LOCK_RULES,
     ],
     "inventory": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1758,6 +1789,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
         _rule_reconcile_pagination_proof,
     ],
     "issue_selection": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_shared_controller_handoff,
         _rule_shared_state_handoff_next_action,
         _rule_shared_email_disclosure,
@@ -1771,6 +1803,7 @@ _RULES_BY_TASK: dict[str, list[Callable[..., list[dict[str, str]]]]] = {
     # Kept intentionally narrow so a closure pre-check does not demand the
     # full reviewer/author handoff schema.
     "controller_close": [
+        *_SHARED_SELF_PROPAGATING_HANDOFF_RULES,
         _rule_reviewer_premerge_baseline_proof,
     ],
 }