fix(simple_metrics): skip invalid interval_minutes and restart a malformed healthy_streak (SIENTIAPDE-2191)

- interval_minutes is untyped Mongo config: a string or null now warns and
  skips the adaptive state instead of failing every run (TypeError).
- A hand-edited healthy_streak (null, text, inf) restarts the count and keeps
  escalated, instead of raising on every run.
- README: step 4 runs on every schedule, so a MongoDB failure fails the run.

tests/laborious/activities/test_model_metrics.py

@@ -1267,6 +1267,9 @@ def _state(escalated: bool, streak: int) -> dict:
         (_state(True, 2), False, 3, _state(False, 0)),  # N-th healthy run recovers
         (_state(True, 2), True, 3, _state(True, 0)),  # breach resets the streak
         (_state(True, 0), False, 1, _state(False, 0)),  # N=1 recovers on first healthy run
+        (_state(True, None), False, 3, _state(True, 1)),  # hand-edited streak restarts
+        (_state(True, 'x'), False, 3, _state(True, 1)),
+        (_state(True, float('inf')), False, 3, _state(True, 1)),
     ],
 )
 def test_next_adaptive_state(state, breached, runs, expected):

tests/laborious/activities/test_mongo.py

@@ -322,6 +322,22 @@ def test_adaptive_state_invalid_frequency_alert_is_skipped(
     mongo_activities.warning.assert_called_once()
 
 
+@mark.parametrize('interval_minutes', ['60', None])
+def test_adaptive_state_invalid_interval_minutes_is_skipped(
+    mongo_activities, mongo, interval_minutes
+):
+    # Untyped Mongo config: "60" * 60 is a string, None * 60 a TypeError.
+    mongo.find_one.return_value = _pipeline(frequency_alert='5m')
+
+    result = mongo_activities.update_simple_metrics_adaptive_state(
+        {**_BREACH_INPUT, 'interval_minutes': interval_minutes}
+    )
+
+    assert result is None
+    mongo.update_one.assert_not_called()
+    mongo_activities.warning.assert_called_once()
+
+
 @mark.parametrize('adaptive_state', ['garbage', ['escalated']])
 def test_adaptive_state_malformed_state_is_not_escalated(mongo_activities, mongo, adaptive_state):
     mongo.find_one.return_value = _pipeline(frequency_alert='5m', adaptive_state=adaptive_state)