Reduce machine max MCP response size

tests/test_calculation_api.py

@@ -5,6 +5,7 @@ import unittest
 from unittest.mock import patch
 
 import app as rollcalc_app
+from machine_constraints import calculate_machine_max_product_length
 
 
 class CalculationApiTests(unittest.TestCase):
@@ -140,21 +141,24 @@ class CalculationApiTests(unittest.TestCase):
         self.assertEqual(result["warning_constraints"], ["roll_diameter_mm"])
 
     def test_machine_maximum_length_endpoint_is_authenticated_and_structured(self):
+        payload = {
+            "machine": "K7",
+            "core_diameter_mm": 133,
+            "thickness_mm": 4.311611,
+            "thickness_stddev_mm": 0.249999,
+            "product_width_m": 6,
+            "area_weight_g_m2": 495.395833,
+        }
         response = self.client.post(
             "/api/calculations/machine-max-product-length",
-            json={
-                "machine": "K7",
-                "core_diameter_mm": 133,
-                "thickness_mm": 4.311611,
-                "thickness_stddev_mm": 0.249999,
-                "product_width_m": 6,
-                "area_weight_g_m2": 495.395833,
-            },
+            json=payload,
             headers=self.headers,
         )
         result = response.get_json()
         self.assertEqual(response.status_code, 200)
         self.assertEqual(result["status"], "success")
+        self.assertEqual(result, calculate_machine_max_product_length(**payload))
+        self.assertIn("final_feasibility", result)
         self.assertEqual(
             result["production_maximums"]["nominal_governing_constraints"],
             ["roll_diameter_nominal"],