Card: point notebook link at docs/examples

Card: sync links with the reorganized code repo

Card: enable the data viewer on the starter-slice files

Card: quickstart snippet, dev_mini, task-based truth-file descriptions

Add DOI and full author list to the card and datasheet

Reduce the grid to 2x2: drop simple cells; correct the intervention count to 16

Add datasheet; document the reference-prediction tree

Withhold store demographics: drop household_count from stores_public; refresh manifests and datasheets

Reflow dataset card to natural line lengths

Add files using upload-large-folder tool