Store each client's play queue in the database

The queue lived in memory and was shared by all clients, so a restart or a
finished sync cleared it. Every client now has its own queue in the new
queue and queue_song tables (added to the undeployed migration 000006).

The music endpoints return the queue ID in the X-Queue-Id header and expect
it back. A request without an ID, or with an ended one, starts a new queue.
/music/reset ends the queue and returns a new ID, and a sync ends all
running queues. Ended queues are kept as history.

The deprecated legacy routes without the /api/v1 prefix are removed.

internal/db/repository/querier.go

@@ -13,6 +13,9 @@ import (
 
 type Querier interface {
 	AddHashToSong(ctx context.Context, arg AddHashToSongParams) error
+	// Appends the queue's last fetched song and makes it the current song.
+	// Does nothing when no song has been fetched since the last call.
+	AddLastFetchedToQueue(ctx context.Context, argUuid uuid.UUID) error
 	AddSong(ctx context.Context, arg AddSongParams) error
 	AddSongPlayed(ctx context.Context, arg AddSongPlayedParams) error
 	AddSongPlayedByUUID(ctx context.Context, argUuid uuid.UUID) error
@@ -23,9 +26,12 @@ type Querier interface {
 	ClearSongs(ctx context.Context) error
 	ClearSongsBySoundtrackId(ctx context.Context, soundtrackID int32) error
 	ClearSoundtracks(ctx context.Context) error
+	CreateQueue(ctx context.Context) (Queue, error)
 	CreateSession(ctx context.Context, arg CreateSessionParams) (Session, error)
 	DeleteExpiredSessions(ctx context.Context) error
 	DeleteSession(ctx context.Context, token string) error
+	EndActiveQueues(ctx context.Context) error
+	EndQueue(ctx context.Context, argUuid uuid.UUID) error
 	FetchAllSongs(ctx context.Context) ([]Song, error)
 	FindAllSoundtracks(ctx context.Context) ([]Soundtrack, error)
 	FindSongsFromSoundtrack(ctx context.Context, soundtrackID int32) ([]Song, error)
@@ -48,6 +54,7 @@ type Querier interface {
 	GetNeverPlayedSoundtracks(ctx context.Context) ([]GetNeverPlayedSoundtracksRow, error)
 	// Oldest played soundtracks (least recently played, but has been played at least once)
 	GetOldestPlayedSoundtracks(ctx context.Context, limit int32) ([]GetOldestPlayedSoundtracksRow, error)
+	GetQueue(ctx context.Context, argUuid uuid.UUID) (Queue, error)
 	GetRandomActiveSong(ctx context.Context) (GetRandomActiveSongRow, error)
 	GetSession(ctx context.Context, token string) (Session, error)
 	GetSongByUUID(ctx context.Context, argUuid uuid.UUID) (Song, error)
@@ -64,12 +71,16 @@ type Querier interface {
 	InsertSongInList(ctx context.Context, arg InsertSongInListParams) error
 	InsertSoundtrack(ctx context.Context, arg InsertSoundtrackParams) (InsertSoundtrackRow, error)
 	InsertSoundtrackWithExistingId(ctx context.Context, arg InsertSoundtrackWithExistingIdParams) error
+	// The song columns are NULL when the song has been removed from the library since.
+	ListQueueSongs(ctx context.Context, queueUuid uuid.UUID) ([]ListQueueSongsRow, error)
 	ListSessions(ctx context.Context) ([]Session, error)
 	MarkSoundtracksDeletedExcept(ctx context.Context, ids []int32) error
 	RemoveBrokenSong(ctx context.Context, arg RemoveBrokenSongParams) error
 	RemoveBrokenSongs(ctx context.Context, uuids []uuid.UUID) error
 	RemoveSoundtrackDeletionDate(ctx context.Context, id int32) error
 	ResetSoundtrackIdSeq(ctx context.Context) (int64, error)
+	SetQueueCurrentSong(ctx context.Context, arg SetQueueCurrentSongParams) error
+	SetQueueLastFetched(ctx context.Context, arg SetQueueLastFetchedParams) error
 	SetSoundtrackDeletionDate(ctx context.Context) error
 	SetSoundtrackFingerprint(ctx context.Context, arg SetSoundtrackFingerprintParams) error
 	UpdateSong(ctx context.Context, arg UpdateSongParams) error