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>