Available is false when the usage warehouse is not connected or its rollup is not ready. Rows is then empty because nothing could be read — not because nobody used anything. Show that difference; never render an unavailable board as a real one.
Period is the window's canonical label: day|week|month|all. The server resolves aliases (7d, 30d, today, …) to these, so this may differ from what was sent.
Rows are the ranked subjects, best first, at most the requested limit of them. Always a list, never null: an empty one means nothing was read, not an error.
Self is the caller's own standing, reported even when they fall outside Rows. Absent when the caller's ledger identity cannot be resolved, or when the query behind it failed — never faked to keep the shape tidy.
Source names the table these numbers were aggregated from (the derived daily rollup, hanzo.usage_rollup_daily), so an operator can tell exactly what was read.
Subject is what the rows stand for — "user" on a personal or org board, "org" on the global one. It tells a client whether Handle names a person or a company.
Total is how many subjects were ranked in the window — the org's active users, or the active/opted-in orgs on the global board. It is the universe the ranks are out of, so it is normally larger than len(rows).
