fix(plotly): remove ~520 lines of duplicate dead box/waterfall functions

The cross-branch merge left two competing implementations of
_append_box_points_to_selection and its helpers, plus duplicate
_build_waterfall_point and _append_map_scatter_points_to_selection.
Python silently used the last definition; pyright caught all six
[no-redef] errors in CI. Removes the dead first copies.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: axsseldz