Category and chain totals for the published asset universe.

Call this for asset counts, pricing coverage, and holder totals. The aggregate market cap is published only when every listed asset has a published on-chain price. Until then market_cap_usd is null, market_cap_withheld is true, every by_category and by_chain row leaves out market_cap_usd, and coverage says how many listed assets are priced. Per-asset market caps from list_assets and get_asset are not affected. When every listed asset is priced, market_cap_usd sums them and each row carries its own market_cap_usd. holders sums only assets with a published holder count. holder_assets is how many assets contributed, so a missing holder count is not treated as zero. Per-chain holder counts include a chain only when that chain published holders.

JSON: {"listed_assets", "priced_assets", "market_cap_usd", "market_cap_withheld", "coverage", "holders", "holder_assets", "by_category": [{category, category_label, assets, priced_assets, market_cap_usd, holders, holder_assets}], "by_chain": [{chain_id, chain, assets, priced_assets, market_cap_usd, holders, holder_assets}], "ethereum_block", "ethereum_block_time", "note"}. An asset on more than one chain is counted in each of those chains. holders is omitted on a row that has no published holder counts. Market cap is US dollars. Each asset keeps its own as_of; chain-native assets can differ from the Ethereum block time.