drawing-to-spec — Architectural Drawing → design_spec.py Extraction

What This Skill Does

Reads an architectural drawing (CD set PDF page, BIM SVG output, or PNG) and extracts labeled dimension values to populate or verify design_spec.py fields.

This is the REVERSE of the normal pipeline direction (FreeCAD → drawings). Use it to:

1. Populate spec fields from CD set drawings when starting a new iteration
2. Verify spec accuracy — confirm design_spec.py matches what the architect drew
3. Detect drift — find fields where the BIM spec has diverged from the stamped CD set
4. Resolve ambiguity — when a dimension is unknown, read it from the authoritative source

The skill never estimates values. Every proposed field change must be backed by a visible dimension label in the drawing. Fields without visible labels are output as CANNOT_VERIFY.