SIENTIAPDE-2212

Add e2e scenario for drift window and chunk_period

- Add scenario 1.8.1: two drift pipelines on frequency 1m. One has no
  interval_minutes and an invalid chunk_period='hour', so it expects
  interval=2, chunk_period='min' and one DRIFT_CHUNK_PERIOD_INVALID
  notification. The other sets interval_minutes=60 and chunk_period='s',
  and both are forwarded unchanged with no warning (SIENTIAPDE-2212).
- Add a _schedule_input helper that decodes the workflow input of a
  laborious-namespace schedule.
- Reformat the ensure_namespace_search_attributes signature in
  conftest.py to a single line.

e2e/scenarios.md

@@ -56,6 +56,14 @@ Laborious-style write (`adaptive_state.escalated=true` + BSON-datetime `updated_
 window → next run switches only that schedule to `frequency_alert`; the recovery write switches it
 back to `frequency`.
 
+### 1.8.1 Drift window and chunk_period
+
+Two `drift` pipelines on `frequency='1m'`: one without `interval_minutes` and with an invalid
+`chunk_period='hour'` → workflow input `interval=2` (frequency + 1-minute margin),
+`chunk_period='min'` and exactly one `DRIFT_CHUNK_PERIOD_INVALID` notification; one with
+`interval_minutes=60` and `chunk_period='s'` → both forwarded unchanged, no warning
+(SIENTIAPDE-2212).
+
 ---
 
 ## 2. Alerts workflow