DIMLINEAR/ALIGNED/RADIUS/DIAMETER/ANGULAR/ARC/ORDINATE/CONTINUE/BASELINE, QDIM, MLEADER, LEADER; HATCH/GRADIENT/BOUNDARY/REGION with pick-point boundary tracing (planar face walk with islands); BLOCK/INSERT/ATTDEF/ATTEDIT/WBLOCK/PURGE/BATTMAN; dimension text gaps and horizontal text; DXF header writer whitelist (correct group codes). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>