Handle stacked PR retarget and merge-queue trigger gaps

.github/workflows/pr-review-merge-scheduler.yml

@@ -4,7 +4,9 @@ on:
   push:
     branches: [main, develop, master]
   pull_request_target:
-    types: [opened, synchronize, reopened, ready_for_review, auto_merge_enabled, closed]
+    # Include retarget/queue/auto-merge state changes so stacked PR chains are
+    # re-evaluated immediately when merge readiness shifts without a new head push.
+    types: [opened, synchronize, reopened, edited, ready_for_review, enqueued, dequeued, auto_merge_enabled, auto_merge_disabled, closed]
   pull_request_review:
     types: [submitted, dismissed]
   workflow_run:

tests/test_required_workflow_queue_contract.py

@@ -38,6 +38,15 @@ def test_merge_scheduler_dispatches_one_review_by_default() -> None:
     )
 
 
+def test_merge_scheduler_pull_request_target_includes_retarget_and_queue_events() -> None:
+    workflow = workflow_text("pr-review-merge-scheduler.yml")
+
+    assert (
+        "types: [opened, synchronize, reopened, edited, ready_for_review, enqueued, dequeued, auto_merge_enabled, auto_merge_disabled, closed]"
+        in workflow
+    )
+
+
 def test_merge_scheduler_provides_same_repository_dispatch_credential() -> None:
     """Guard the runner-token dispatch credential for central review workflows.