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/search.sql

@@ -1,4 +1,4 @@
--- Searching for wants and grabbing releases (M502 #5521).
+-- Searching for wants and grabbing releases.
 
 -- name: GetAcquisitionSettings :one
 SELECT * FROM acquisition_settings WHERE id = true;
@@ -24,7 +24,7 @@ UPDATE acquisition_settings SET last_pass_at = now(), last_pass = sqlc.arg(repor
 -- Wants with no download running that were never searched or not since
 -- @hours ago: open wants first (never-searched, then requests, then missing
 -- files, then followed artists' releases), then held albums wanted for an
--- upgrade (#5524), which are searched at most weekly.
+-- upgrade, which are searched at most weekly.
 SELECT w.id, w.release_group_mbid, w.artist_name, w.title, w.reason, w.upgrade, w.held_tier, w.held_quality,
        COALESCE(NULLIF(w.primary_type, ''), g.primary_type, '')::text             AS primary_type,
        COALESCE(g.secondary_types, '{}')::text[]                                  AS secondary_types,
@@ -120,7 +120,7 @@ UPDATE grabs
 
 -- name: ListReleaseBlocks :many
 -- Every release set aside and still held back: a stalled one lifts by itself
--- at expires_at (#5523).
+-- at expires_at.
 SELECT * FROM release_blocks
  WHERE expires_at IS NULL OR expires_at > now()
  ORDER BY blocked_at DESC;