Milestone #160 Opt 2 (era half). A third taste facet alongside artists
+ genre tags: signed weights over decade buckets ("1990s") derived from
albums.release_date, rebuilt daily and scored into the taste match.
- Migration 0045: taste_profile_eras table (mirrors taste_profile_tags)
+ taste_tuning.era_scale column (DEFAULT 0.5).
- Build side (internal/taste): Config.EraScale ([0,1] damper, mirrors
EnrichedTagScale), accumulate folds each play/like's decade at
base*EraScale, persist atomic-replaces the era rows.
- Scorer (internal/recommendation): TasteProfile gains an era term (own
tanh scale + additive 0.15 share so it never weakens the existing
artist/tag signal when a track is undated); candidate queries return
album release_date; decadeOf mirrors the builder helper.
- Tuning lab: era_scale threaded through recsettings + admin API + web
card (auto-renders the new row) + Go/web tests.
Mood facet deferred to #1534 (partial enrichment coverage + needs
candidate-side enriched-tag loading).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The profile built in phase 1 now changes what gets surfaced. Adds a TasteMatch
term to the weighted-shuffle score so candidates are re-ranked by their fit to
the user's learned taste (positive draws toward it; negative reflects passive
avoidance; 0 at cold start).
- recommendation/score.go: ScoringInputs.TasteMatchScore ([-1,+1]) +
ScoringWeights.TasteWeight + the term in Score.
- recommendation/taste.go: LoadTasteProfile reads the taste_profile_* tables;
TasteProfile.Match blends the candidate's artist weight (0.7) and avg genre-tag
weight (0.3), each tanh-squashed by a fixed scale so one outlier artist can't
compress the rest. Unknown artist/tags and empty profiles → 0 (neutral).
- candidates.go: both candidate loaders set TasteMatchScore per candidate, so
every Score caller (system playlists incl. You-might-like, radio) becomes
taste-aware automatically.
- weights: systemMixWeights.TasteWeight = 1.5 (daily mixes are the primary
taste surface); config.RecommendationConfig gains taste_weight (default 1.0,
lighter — radio is seed-directed) wired into the radio handler.
- tests: pure (Match curve incl. saturation/clamp/empty-neutral, Score term
add+subtract) + DB round-trip (seed taste rows → Match positive). All green
vs real Postgres; existing playlist/radio tests unaffected (empty profile →
zero taste effect).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
bvandeusen