SIENTIAPDE-2011: add e2e coverage for query-time filter, fix stale e2e fixtures

e2e fixtures (default_notification, seed_last_timestamp, default_receiver_group)
still assumed the pre-SIENTIAPDE-2007 string-timestamp representation and the
old ignore_models field name, so the load_notification_package e2e suite was
failing independently of this ticket's changes:

- default_notification now seeds `timestamp` as a native datetime (matches
  production since SIENTIAPDE-2007's Notification.timestamp = now()).
- seed_last_timestamp now uses DATETIME_FORMAT_MS_WITH_TZ (matches what
  put_last_data_timestamp actually writes to Redis today).
- default_receiver_group's ignore_models renamed to ignore_models_id, per
  this ticket's decision.
- test_reports_main_workflow.py's explicit timestamp= call sites updated to
  match.

Also fixes a real production bug in put_last_data_timestamp (slot_manager.py)
surfaced by running the e2e suite against a real Temporal environment: Temporal's
default data converter serializes datetime values to ISO-8601 strings across
the activity boundary, and pymongo returns naive datetimes for BSON Date
fields, so `data['timestamp'].max().strftime(...)` crashed on a plain str.
Unit tests never caught this because they mock the activity boundary and
never cross real (de)serialization. Fixed by normalizing through
`pandas.to_datetime(..., utc=True)`, which handles native datetime/Timestamp
and offset-aware/naive ISO strings uniformly.

Adds test_load_package_query_time_filter_union_and_intersection, a new e2e
test exercising the actual SIENTIAPDE-2011 behavior end-to-end: union of
active groups' levels, intersection of their ignore_models_id, and the
requirement that a model ignored by only one of several active groups must
not be excluded from the fetch.

Note: test_reports_main_workflow.py / test_alerts_main_workflow.py still have
a separate, pre-existing failure in process_notifications.py (same family of
bug: a notification's timestamp field parsed with a fixed strptime format
after crossing the same Temporal serialization boundary) — confirmed present
on the unmodified baseline too, unrelated to this ticket, tracked separately.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

e2e/scenarios.md

@@ -71,7 +71,12 @@ Alert past `notification_ttl` with cache cleared → new email sent.
 
 ### A.2.1 Group filtering
 
-Receiver group `levels` / `ignore_models` honored.
+Receiver group `levels` / `ignore_models_id` honored. The query-time half
+(union of `levels`, intersection of `ignore_models_id` across active groups)
+is covered at the subworkflow level — see `LoadNotificationPackage` below.
+The per-group half (each group only receiving its own precise slice) is not
+yet implemented in production code (SIENTIAPDE-2012) and so is not yet
+exercised here.
 
 ### A.3.1 Empty queue
 
@@ -103,6 +108,7 @@ No notifications → no SMTP, no Postgres row.
 
 - No prior Redis timestamp → all matching notifications returned, max timestamp stored.
 - Prior timestamp → only newer notifications returned.
+- Query-time filter (SIENTIAPDE-2011) → union of active groups' `levels`, intersection of their `ignore_models_id`; a model ignored by only one of several active groups is not excluded from the fetch.
 - Empty Mongo → no Redis timestamp write.
 
 ### ProcessNotifications — `e2e/test_subworkflow_process_notifications.py`