Add fail-closed Belgian training loop

backend/tests/test_belgium_training_portfolio.py

@@ -19,10 +19,10 @@ def test_portfolio_covers_every_region_split_and_context_family() -> None:
     assert len({aoi.slug for aoi in module.AOIS}) == len(module.AOIS)
     counts = Counter((aoi.region, aoi.split) for aoi in module.AOIS)
     for region in module.REGION_CONTRACT:
-        assert counts[(region, "train")] >= 6
+        assert counts[(region, "train")] >= 10
         assert counts[(region, "val")] >= 2
-        assert counts[(region, "calibration")] >= 2
-        assert counts[(region, "test")] >= 2
+        assert counts[(region, "calibration")] >= 3
+        assert counts[(region, "test")] >= 3
         assert counts[(region, "background-test")] >= 2