A selected pin was drawn only 1 px bigger and slightly brighter. Now, like
selected and unselected mask vertices in the viewer, a selected pin is
filled with its kind colour and ringed in white, and an unselected pin is
hollow (dark centre, coloured outline). Drawing only; hit-testing is
unchanged.
Regression test: selected_puppet_pins_are_filled_and_unselected_hollow.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
(cherry picked from commit 103b5c41e9e8ea84008593e05af50b01a2800b3e)