Re-organized repo - #158

…h-bench #156)

Keep the fixed synthetic data (Zipf s=1.1 over 10,000 keys, quantiles on
the Zipf ranks) and top-k with k in {100, 200, 300} served by heap-K
deployments. Everything else follows sketch-bench #156/#162:
- sketch accuracy from the saturation curves at n(S, G); CPU, memory and
  exact rows from the cost table; grid configs only.
- merging: every pane saturated, then read at n(S, G); KLL/top-k merge
  penalty is #158. AutoSketch uses the same lookup with m = 1.
- DDSketch scored in value relative error (#162), with its own targets.
- a targeted saturation run at the workload's data shape (theta 1.1,
  K 1e4, Zipf-rank quantiles, CMS-heap heaps 100/200/300) so lookups land
  on measured points.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>