- Score and boost contributions now captured per candidate in signal_snapshot:
score_by_sort() returns (f64, Vec<(String, f64)>) with named signal values
(e.g. view_velocity, share_velocity, view, like). Boost contributions are
appended as `{signal}_boost`. compute_raw_score() threads the snapshot
through; score_inner() and score_personalized() write it onto ScoredCandidate
instead of always initialising to vec![].
- Quickstart switched from `trending` to `hot` profile. The trending profile
scores by 24h velocity, which requires signals to arrive over real elapsed
time to populate hour-level bucket aggregates — impossible in a self-contained
demo. The hot profile (AllTime view count + age decay) works with any timestamp
and produces clearly differentiated scores. Signals now use different counts
per item to drive meaningful ranking output.
