sched: checkpoint-first reconcile across torn checkpoint/summary writes (F2)

tests/scheduling/controlled.py

@@ -88,3 +88,24 @@ class ScriptedDispatcher:
     def finish(self, admission: RunAdmission, outcome: str) -> RunState:
         """Build the stopped state that settles a hanging run."""
         return stopped_state(admission, outcome)
+
+
+class WorkflowDispatcher:
+    """Execution double driving a real workflow to its first stopped state.
+
+    Dispatch runs the workflow through the genuine ``wf_core`` runtime and
+    returns the resulting stopped state, so scheduler tests exercise real
+    execution (including durable interruptions) without enabling any server.
+    """
+
+    def __init__(self, workflow: Any, registry: dict[str, Any] | None = None) -> None:
+        self.workflow = workflow
+        self.registry = registry or {}
+
+    def dispatch(self, *, admission: RunAdmission, now: datetime) -> DispatchResult:
+        from wf_core import execute_workflow
+
+        state = execute_workflow(
+            self.workflow, dict(admission.resolved_input), self.registry
+        )
+        return Stopped(result=state)