Straighten a curved ribbon

Start with: examples/skadira/curved-ribbon.blend: a fictional ribbon of 4 quads bent through 90 degrees, whose UVs follow the curve. All four faces are already selected.

1. Install Skadira as above, then open examples/skadira/curved-ribbon.blend with File › Open….
2. Click the object Curved ribbon, press Tab for Edit Mode and open the sidebar's Skadira tab with N.
3. Click Validate Selection.
4. Click Straighten Strip, then look at the UVs in the UV Editor (for example in the UV Editing workspace).

Expected result: Validate reports a valid strip: 4 quads, 5 cross-sections, uniform spacing, rectangle 0.7023 x 0.1000 UV, and nothing changes. Straighten Strip turns the curved UV arc into a straight rectangle of the same size with five evenly spaced cross-sections, inside the 0 to 1 UV square. The mesh does not move. Ctrl+Z brings the curve back.

All examples are fictional or synthetic.
