Period roll-up pages from persisted daily rankings: count "days seen of days recorded", exclude list-everything boards, and give reused sections a no-write mode

A daily anomaly report persisted each board's rows to a history table, and the operator then asked for weekly and monthly reports. Reusing the daily section builders for the period pages had two traps: those builders wrote their rows to the history table as "today's" record, so a period page rebuilt with a different window silently overwrote the daily record; and one board that lists every tracked entity every day (a universe list, not a ranking) made every entity a "seen every day" regular in the roll-up. Early in the history, "seen 3 days" also read as strong when only 3 days had ever been recorded.

Build the period page around the one thing only it can say: persistence. Roll the history table up per entity over the last N days: days seen, which boards and how many days each, best showing (best rank; at equal rank prefer the row with the most agreeing streams), first/last day, and print days seen AS A SHARE of days actually recorded in the window ("3 of 3 recorded days") with a note when the history is younger than the window. Exclude boards that list the whole universe every day from the roll-up and say so on the page. Give every reused section builder a record=False keyword so the period page renders from the same functions without touching the history, and let window-dependent sections take their window as parameters and label the table headers from them. Wrap each section in a guard that turns an exception into one visible line so one failure never costs the page. Verify by counting history rows before and after rendering the period pages: they must be equal.

Daily observation reports with per-board persistence in SQLite, when adding weekly/monthly views that reuse the daily section builders.