Sync README.md with PR 92 fixes: add 100k sample row + dataset/bucket twin note

Sync inventory.json with PR 92 fixes: 100k sample twin cataloged + dolma3-6t-dolma3-6t-preconditioner-100k typo fixed

PR 3b: add 100k sample dataset twin to inventory

PR 3b: add 8 sub-collection links to README

PR 3 update: 31 renames + naming-convention rule + collection field

Update inventory + README after TrackStar rename + SOC# drop (2026-05-24)

Add noprecond bucket entry to inventory after gap-fill upload

Final soc91-labels mirror numbers (2719 chunks, 169.94 GB)

Interim refresh: add HF mirrors of soc91-labels (in-progress), soc91-stats, soc139-quality-sidecars

Initial data-home: README + inventory.json

initial commit