fix: honor live scheduling revisions at dispatch

tests/scheduling/test_poll.py

@@ -13,8 +13,8 @@ from tests.scheduling.controlled import (
 )
 from wf_artifacts.runs.models import StoredRunStatus
 from wf_artifacts.runs.store import FileRunStore
-from wf_scheduling.calendar import OneShotSource
-from wf_scheduling.models import Schedule
+from wf_scheduling.calendar import CronSource, OneShotSource
+from wf_scheduling.models import CronTrigger, Schedule
 from wf_scheduling.ownership import SchedulerOwnership
 from wf_scheduling.poll import SCAN_CAP, Scheduler
 from wf_scheduling.prepare import SchedulePreparer
@@ -249,6 +249,34 @@ def test_schedule_edit_between_poll_snapshot_and_admission_cannot_overwrite_term
         sched.ownership.release()
 
 
+def test_trigger_edit_refreshes_managed_calendar_before_polling(tmp_path: Path) -> None:
+    """A trigger edit cannot be paired with the previous tick's source."""
+    sched, store, runs, sources = _harness(tmp_path, script={"*": "complete"})
+    start = ts(2026, 9, 8, 11, 0)
+    now = ts(2026, 9, 8, 12, 0)
+    _add(
+        sched,
+        store,
+        sources,
+        "a",
+        CronSource("0 * * * *", "UTC"),
+        start,
+    )
+    old_trigger = store.get_schedule("a").trigger
+    sched.set_source_definitions({"a": old_trigger})
+    edited = store.get_schedule("a")
+    edited.revision = 2
+    edited.trigger = CronTrigger(
+        expression="0 13 * * *",
+        timezone="UTC",
+    )
+    store.update_schedule(edited, expected_revision=1)
+
+    assert sched.poll(now) == {"a": "idle"}
+    assert runs.list_admissions() == []
+    sched.ownership.release()
+
+
 def test_parallel_limits_and_interrupted_slots() -> None:
     import tempfile