Flatten used the vector's network as stored, so a rounded point kept its radius and the box kept the cut-off sharp vertex. It now takes the network as the layer draws it (VectorNetwork::rounded_smoothed through geometry::drawn_network): each rounded point becomes the arc's end points joined by curves, every radius reads 0, and the layer's box is re-fitted to the baked geometry. Shapes' own radii were already baked; a rounded point beside a curved segment keeps today's behaviour.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Model-Effort: Opus 5.5 drove; Opus 5.5 briefed; Sonnet 5.5 wrote at medium
