Replace the single stacked config pane with a top tab strip (Pack, Cells, BMS,
Busbars) so only one group is visible at a time. Pack sizing defaults to
Series × Parallel with a summary chip that shows count and footprint, with a
mm-size mode for users who prefer direct dimensions. Cells and Housing are
merged under one tab separated by a divider.
Exports are now per component: the cellholder is a STEP solid, and each busbar
downloads as either STEP (3D stencil) or DXF (flat laser cut pattern) chosen by
a dropdown. Mirrored and rotated duplicates are deduplicated by a
pairwise-distance signature so only one copy per shape class is emitted.
The DXF writer produces just the union outline: pads as CIRCLE or ARC entities
restricted to uncovered angular ranges, capsule sides as LINE entities clipped
(Liang-Barsky + disc intersection) against every other primitive so no lines
remain inside the busbar body.
README documents setup, features, and project layout.
