The Family dropdown was too small to comfortably click on the Flake
Stack node and clicks were leaking to the LiteGraph canvas on the
Flake Model Preset node, where they triggered the underlying preset
combo. Increase font size, padding, and min-height across all four
widgets, and stop mousedown/click propagation so the canvas no longer
intercepts dropdown opens.
Also introduce a shared FAMILY_FOLDERS / familyFolder helper in utils
to be used by upcoming path-aware features.