The Home hero's surprise tier and the Plex Discover rail were uniform draws over the unseen. They
are now weighted draws (`app.draw`, Efraimidis-Spirakis over the same md5 shuffle): a title's
weight is 1 + its affinity. Plex: the genres of the latest watched titles (half-life 180 days, a
show counts once) and the TMDB recommendations stored on them (`plex.affinity`). YouTube: the
channels the user watches (half-life 90 days). One slot of three stays a blind draw, and with no
history the order is exactly the old one. No visible change.
The YouTube draw builds its pool once (a materialized CTE read twice): the scope is ~200k videos on
a prod-sized catalog, and a second ordered pass doubled the cost. Measured on localdev: a reroll
210 -> 292 ms.
peter
9310ff85bf