perf: simplify embedding heuristics

[mplatzer]

Note

Streamlines embedding size computation in TabularARGN.

• Updates _embedding_heuristic to drop the max(10, ...) floor; sizes are now S=2*ceil(dim^0.15), M=3*ceil(dim^0.25), L=4*ceil(dim^0.33), still capped by dim_input
• Pre-commit: comment out --use-current-year for insert-license

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