a3d 0.9.2

[0.9.2] - 2026-09-12

Transparency, which a3d does not have and had not been saying so. A glTF
material marked alphaMode: BLEND is not drawn faint by this renderer, it is
drawn solid - and the importer had been ignoring the field without a word.

Added

• --drop-blend for a3d_export.py: leave out primitives whose glTF material
  is alphaMode: BLEND or MASK.

Changed

• A non-opaque material now warns on every import. a3d writes every covered
  pixel opaquely - there is no alpha blend and no alpha test - and the importer
  had been ignoring alphaMode silently. The shapes authored for BLEND are the
  ones meant to be nearly invisible (a propeller blur disc, a soft shadow quad,
  a glow card), so they are large and they sit in front of the model.

  They are also in worldBounds(), which is the half that does not look like a
  transparency problem: on one stylized aircraft 40 triangles of 7,692 inflated
  the bounding box from 1.37 to 3.24 and pushed the framing camera 2.4x too far
  back. The vertex, triangle, material and texture counts were all correct, so
  nothing that counts could see it - the same shape as the Draco import this
  project already refuses by name.