Standalone coordinate viewer driven by transformed DXF world-space points. Electrical uses the exact axis transform you specified, HVAC uses a separate exact affine fit through the three known indoor-unit anchors, and annotation callouts use those transformed coordinates directly with no visual nudging.
Electrical anchor check: your requested electrical formula maps DXF (61.0, 21.2) to SVG (327.6, 140.3), not the stated (228, 188). This page keeps the formula output exactly as calculated and does not hand-correct that inconsistency.
The room frame below is a simple mathematical reference frame built from the stated SVG wall extents and split lines only: left/right 0/737, top/bottom 0/431, vertical split x=228, horizontal split y=188. No prior floor-plan drawing geometry is reused.