Test safe checkpoint cadence

tests/test_training_modes.py

@@ -12,6 +12,8 @@ def test_training_modes_are_isolated_and_conservative():
     assert MODE_DEFAULTS["full"]["subset_size"] is None
     assert MODE_DEFAULTS["pilot"]["batch_size_per_gpu"] <= 1200
     assert MODE_DEFAULTS["full"]["grad_accumulation_steps"] >= 2
+    assert MODE_DEFAULTS["smoke"]["save_every"] >= 100000
+    assert MODE_DEFAULTS["overfit"]["save_every"] >= 100000
 
 
 def test_explicit_trainer_script_is_used(tmp_path: Path):