PR Summary:

• Adds optional color parameter (DB.ColorWithTransparency, default None) to Mesh.from_solid
• When provided, the color is applied uniformly to all faces, bypassing per-face material lookup
• Original per-face material color behaviour preserved when color=None
• Developer example UI updated with a CheckBox to toggle color override in button_select

Review Summary:

The core logic change in dc3dserver.py is clean and correct — renaming the loop variable from color to face_color properly avoids shadowing the new parameter. The conditional priority (color override → by-category fallback → material lookup) is correct.

Two minor bugs were found in the example/demo code: the CheckBox.IsChecked nullable bool check is non-idiomatic for IronPython WPF interop, and the checkbox lacks Grid.ColumnSpan="2" in the XAML causing it to render in only the narrow label column. A docstring inconsistency was also flagged: Raises: TypeError is documented but the exception is silently swallowed by the bare except: block.

Follow-up suggestions:

• @devloai fix the identified issues (nullable bool check, ColumnSpan, and misleading Raises docstring)