fix(recommendation): drop user_id from Rediscover daily hash to preserve sqlc type inference

CI on 8b586c2e caught it: the $1::text cast in the md5 ORDER BY made
sqlc infer the parameter as plain string instead of pgtype.UUID,
generating Column1 string instead of UserID pgtype.UUID on the
ListRediscover*ForUserParams structs. go vet flagged both call
sites in internal/recommendation/home.go where the Go code passes
UserID by name.

Fix: hash on album_id (or artist_id) + current_date only. The
eligibility filter already differs per user (different liked sets),
so the daily-rotation goal is preserved; we just lose per-user salt
in the within-day ordering of overlapping items - acceptable.

Applies to both primary queries AND both fallback queries (all four
had the same cast).

internal/db/queries/recommendation.sql

@@ -313,7 +313,7 @@ SELECT sqlc.embed(albums), artists.name AS artist_name
 FROM eligible e
 JOIN albums  ON albums.id = e.album_id
 JOIN artists ON artists.id = albums.artist_id
-ORDER BY md5(albums.id::text || $1::text || current_date::text)
+ORDER BY md5(albums.id::text || current_date::text)
 LIMIT $2;
 
 -- name: ListRediscoverAlbumsFallbackForUser :many
@@ -321,13 +321,16 @@ LIMIT $2;
 -- service uses this to top up the rediscover row when the primary
 -- eligibility query returns fewer than the inner limit. Same daily
 -- hash ordering as the primary so the fallback rows stay stable
--- through the day instead of reshuffling on every refresh.
+-- through the day instead of reshuffling on every refresh. Hash
+-- omits user_id so sqlc can keep the user_id parameter UUID-typed
+-- (a $1::text cast would force the param to string); eligibility
+-- already differs per user, so output sets differ regardless.
 SELECT sqlc.embed(albums), artists.name AS artist_name
 FROM general_likes_albums gla
 JOIN albums  ON albums.id = gla.album_id
 JOIN artists ON artists.id = albums.artist_id
 WHERE gla.user_id = $1
-ORDER BY md5(albums.id::text || $1::text || current_date::text)
+ORDER BY md5(albums.id::text || current_date::text)
 LIMIT $2;
 
 -- name: ListRediscoverArtistsForUser :many
@@ -381,13 +384,14 @@ LEFT JOIN LATERAL (
     SELECT count(*) AS album_count
     FROM albums WHERE artist_id = artists.id
 ) cnt ON true
-ORDER BY md5(artists.id::text || $1::text || current_date::text)
+ORDER BY md5(artists.id::text || current_date::text)
 LIMIT $2;
 
 -- name: ListRediscoverArtistsFallbackForUser :many
 -- Daily-stable random sample of liked artists, paired with the Go
 -- top-up logic in HomeData when the primary eligibility query returns
--- fewer than the inner limit. Daily hash ordering matches the primary.
+-- fewer than the inner limit. Daily hash ordering matches the primary
+-- (omitting user_id from the hash for the same sqlc-typing reason).
 SELECT sqlc.embed(artists),
        cov.id AS cover_album_id,
        cnt.album_count::bigint AS album_count
@@ -403,5 +407,5 @@ LEFT JOIN LATERAL (
     FROM albums WHERE artist_id = artists.id
 ) cnt ON true
 WHERE gla.user_id = $1
-ORDER BY md5(artists.id::text || $1::text || current_date::text)
+ORDER BY md5(artists.id::text || current_date::text)
 LIMIT $2;