CAM: store tool quantities in user units, not metric

src/Mod/CAM/CAMTests/TestPathToolBitSerializer.py

@@ -96,7 +96,7 @@ class TestFCTBSerializer(_BaseToolBitSerializerTestCase):
         self.assertEqual(data.get("name"), "Test Tool")
         self.assertEqual(data.get("shape"), "endmill.fcstd")
         self.assertEqual(data.get("parameter", {}).get("Diameter"), "4.12 mm")
-        self.assertEqual(data.get("parameter", {}).get("Length"), "15.0 mm", data)
+        self.assertEqual(data.get("parameter", {}).get("Length"), "15.00 mm", data)
 
     def test_extract_dependencies(self):
         """Test dependency extraction for FCTB."""

src/Mod/CAM/Path/Tool/toolbit/util.py

@@ -25,7 +25,7 @@ import FreeCAD
 def to_json(value):
     """Convert a value to JSON format."""
     if isinstance(value, FreeCAD.Units.Quantity):
-        return str(value)
+        return value.UserString
     return value