Parse graphical elements (rectangle, polyline, circle, arc, bezier) from
lib_symbols definitions to compute accurate symbol bounding boxes instead
of relying on pin positions with hardcoded degenerate expansion. This
fixes bbox accuracy for ICs (previously too small), tiny 2-pin passives
(previously too large), and single-pin symbols.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>