FAIR Digital Object Squirrel Implementation (FDOSquirrel)

First release verified end-to-end against fdo-3d-packager's real output (CIIC 81, Freshford; fdo-3d-packager commit 7ddf1a8). Highlights since v0.3.1: correct fdo:role classification for .mtl/viewer//data/textures/ (S18), PNG+SVG-only diagram output (S19), optional creators[].id (S20), fixed auxiliary-role/CC-license/file-count/placeholder gaps in the overview diagram (S21). Known limitation: no automated tests/CI yet - verification has been per-change, against fresh clones and real production data, documented in PRIMER.md.