doom.build_actors

Bakes the monster 8-rotation walk billboard atlases (doomspr_<base>_walk_r1..8 + sprq_<base> quads) from the WAD for the shareware actors (POSS/SPOS/TROO/SARG/BOSS), with a radial fallback to rotation 1. A content-generation tool run via @root::doom.build_actors; uses doom.sprite_decode.