- 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.
Rename PredictionMetadata (prediction_metadata.py) to MongoActivities (mongo.py) and move update_simple_metrics_adaptive_state there from ModelMetrics, so both Mongo-backed activities share one class and repository (PR #59 review, agreed with the class author). write_prediction_metadata is unchanged; the pure hysteresis helpers stay in model_metrics.py. References in activities.py, docstrings and tests updated.
