fix(scheduler): address !7 REQUEST_CHANGES

- seed: check completed_key before no_source so same-day last_completed
  is already_completed (not 10m retry)
- scheduler: resolve TaskControl ok/error before logging; ok=False logs
  task_fail, not task_ok
- candidate_cleanup: catch failures, record task, retry ~5m like discover

tests/test_scheduler.py

@@ -152,10 +152,87 @@ def test_task_control_overrides_ok_and_next_run():
     assert task.next_run == 2_000.0
 
 
+
+
+class _CaptureLogger:
+    def __init__(self):
+        self.events = []
+
+    def info(self, event, **fields):
+        self.events.append(("info", event, fields))
+
+    def warning(self, event, **fields):
+        self.events.append(("warning", event, fields))
+
+    def error(self, event, **fields):
+        self.events.append(("error", event, fields))
+
+
+def test_task_control_ok_false_logs_fail_not_ok():
+    """TaskControl(ok=False) 不得记 scheduler.task_ok（Skip ≠ success）。"""
+    clock = [1_000.0]
+    logger = _CaptureLogger()
+    task = ScheduledTask(
+        "quiet",
+        60,
+        lambda: TaskControl(ok=False, next_run=1_500.0, error="snapshot_quiet_window"),
+    )
+    scheduler = Scheduler([task], clock=lambda: clock[0], logger=logger)
+    results = scheduler.run_due()
+    assert results[0].ok is False
+    assert results[0].error == "snapshot_quiet_window"
+    assert ("info", "scheduler.task_ok", {"task": "quiet"}) not in logger.events
+    fail_events = [e for e in logger.events if e[1] == "scheduler.task_fail"]
+    assert len(fail_events) == 1
+    assert fail_events[0][0] == "warning"
+    assert fail_events[0][2]["task"] == "quiet"
+    assert fail_events[0][2]["error"] == "snapshot_quiet_window"
+
+
+def test_task_control_ok_true_still_logs_task_ok():
+    clock = [1_000.0]
+    logger = _CaptureLogger()
+    task = ScheduledTask(
+        "ok_task",
+        60,
+        lambda: TaskControl(ok=True, next_run=1_200.0),
+    )
+    scheduler = Scheduler([task], clock=lambda: clock[0], logger=logger)
+    results = scheduler.run_due()
+    assert results[0].ok is True
+    assert ("info", "scheduler.task_ok", {"task": "ok_task"}) in logger.events
+    assert not any(e[1] == "scheduler.task_fail" for e in logger.events)
+
+
+def test_raised_exception_logs_task_fail():
+    clock = [100.0]
+    logger = _CaptureLogger()
+
+    def boom():
+        raise RuntimeError("db down")
+
+    scheduler = Scheduler(
+        [ScheduledTask("bad", 10, boom)],
+        clock=lambda: clock[0],
+        logger=logger,
+    )
+    results = scheduler.run_due()
+    assert results[0].ok is False
+    assert results[0].error == "db down"
+    assert not any(e[1] == "scheduler.task_ok" for e in logger.events)
+    assert not any(e[1] == "scheduler.task_fail" for e in logger.events)
+    err_events = [e for e in logger.events if e[1] == "scheduler.task_error"]
+    assert len(err_events) == 1
+    assert err_events[0][0] == "error"
+    assert err_events[0][2]["error"] == "db down"
+
 def main():
     test_run_when_due_and_reschedule()
     test_next_run_fn_controls_reschedule()
     test_task_control_overrides_ok_and_next_run()
+    test_task_control_ok_false_logs_fail_not_ok()
+    test_task_control_ok_true_still_logs_task_ok()
+    test_raised_exception_logs_task_fail()
     test_task_error_does_not_block_other_tasks()
     test_run_forever_with_stop_event()
     test_max_iterations_and_validation()