Operator feedback on the prior unification commit (7473e98d):
1. NewForYou should daily-rotate alongside Rediscover and FirstListens.
The 'newest album first regardless of day' intent was the wrong
call - operator wants visible day-over-day movement on every
deterministic mix surface. Spec flipped to dailyRotate: true.
2. Diversity caps (<=2 per album / <=3 per artist) on every mix, not
just the historically-diverse ones. The 2-per-album limit has
helped a lot on the operator's library; extending it to NewForYou
and FirstListens (previously album-coherent / no cap) surfaces
more distinct albums per day. Spec flipped to diversify: true on
all five.
3. Fallback when diversity caps strip the pool below the 100-track
target: finishMix now calls topUpFromRaw, which appends non-capped
tracks from the raw SQL pool (preserving original ranked order +
skipping duplicates) until the target is hit or the pool runs out.
On rich libraries the cap yields >= 100 and top-up never runs; on
thin / album-heavy libraries we ship a partly-diversified 100
instead of a strictly-diversified 40.
Net effect: every deterministic mix now rotates day-over-day, every
mix gets the same diversity treatment (with graceful degradation),
and the producer surface stays a single factory over a spec list.
bvandeusen
6da6cb5c5a