docs: query comments say what each query selects and why, not how it came to be (#6277)

Rewrites the internal/db/queries comments to rule 32 and regenerates
dbq, whose doc comments and embedded SQL carry them. The bugs behind the
tiered mixes, the md5 order seed, the score bands and the round-robin
arms are restated as the constraint each one enforces; counts from one
library and stale cross-references are gone.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/db/queries/taste_profile.sql

@@ -1,13 +1,13 @@
--- Taste profile (#796 phase 1). The daily build computes signed artist/tag
+-- Taste profile. The daily build computes signed artist/tag
 -- weights in Go (graded engagement + decay + like bonus) and atomic-replaces
--- them here. Read queries serve "top taste" lookups (used in phase 2).
+-- them here. Read queries serve the scorer's "top taste" lookups.
 
 -- name: ListPlayEngagementInputsForUser :many
 -- One row per play in the decay-relevant window. completion is the play's
 -- completion ratio (precomputed column when present, else duration_played /
 -- track duration, clamped to [0,1]); age_days drives the time-decay. Genre
 -- is split into tags in Go; release_date derives the decade for the era
--- facet (#1530). Quarantined tracks are excluded.
+-- facet. Quarantined tracks are excluded.
 SELECT
     t.id AS track_id,
     t.artist_id,
@@ -31,7 +31,7 @@ WHERE pe.user_id = $1
 -- name: ListLikedTrackTasteInputsForUser :many
 -- (track_id, artist_id, genre, release_date) for each track the user has
 -- explicitly liked. Feeds the track-like bonus into the liked track's artist,
--- tags, and era (#1530); track_id keys the enriched track_tags lookup (#1490).
+-- tags, and era; track_id keys the enriched track_tags lookup.
 SELECT t.id AS track_id, t.artist_id, t.genre, a.release_date
 FROM general_likes gl
 JOIN tracks t ON t.id = gl.track_id
@@ -57,7 +57,7 @@ INSERT INTO taste_profile_tags (user_id, tag, weight)
 VALUES ($1, $2, $3);
 
 -- name: ListTasteProfileArtistsForUser :many
--- Top-weighted taste artists (phase-2 consumption + tests).
+-- Top-weighted taste artists, for the scorer and tests.
 SELECT artist_id, weight
 FROM taste_profile_artists
 WHERE user_id = $1
@@ -79,7 +79,7 @@ INSERT INTO taste_profile_eras (user_id, era, weight)
 VALUES ($1, $2, $3);
 
 -- name: ListTasteProfileErasForUser :many
--- Top-weighted taste eras (#1530); consumed by the scorer's era term.
+-- Top-weighted taste eras; consumed by the scorer's era term.
 SELECT era, weight
 FROM taste_profile_eras
 WHERE user_id = $1
@@ -94,7 +94,7 @@ INSERT INTO taste_profile_moods (user_id, mood, weight)
 VALUES ($1, $2, $3);
 
 -- name: ListTasteProfileMoodsForUser :many
--- Top-weighted taste moods (#1534); consumed by the scorer's mood term.
+-- Top-weighted taste moods; consumed by the scorer's mood term.
 SELECT mood, weight
 FROM taste_profile_moods
 WHERE user_id = $1