fix(player+lidarr): mini-player sync race; durable approve + dedup

player: setQueueFromTracks fast-starts a single source at player-index 0
while the full queue is broadcast, so the transient currentIndexStream→0
emission clobbered the correct mediaItem with queue.value[0] (the first
track). Mini bar / playlist marker pinned to the wrong track until a
later index event (~the "passive ~30s recovery"). Track a logical-index
base so the player→queue mapping stays correct during the fill window;
also fixes the latent forward-fill auto-advance off-by-base.

lidarr #50: approving no longer fails when Lidarr is down. Approve
records the decision durably first, then best-effort adds; the
reconciler idempotently (re)sends unconfirmed adds every tick until they
stick (new additive lidarr_add_confirmed_at; AddArtist/AddAlbum map
Lidarr's "already exists" 400 → ErrAlreadyExists). No failed-state or
expiry by design — Lidarr keeps trying, operator monitors.

lidarr #51: Create() is now idempotent — a non-terminal request for the
same MBID returns the existing row instead of inserting a duplicate.

Rewrites the obsolete LidarrUnreachable_503 test to assert the durable-
approve contract; threads a client factory into NewReconciler.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/db/queries/lidarr_requests.sql

@@ -93,3 +93,29 @@ SELECT EXISTS (
         OR (kind = 'album'  AND lidarr_album_mbid  = @mbid)
         OR (kind = 'track'  AND lidarr_track_mbid  = @mbid))
 );
+
+-- name: GetNonTerminalRequestForMBID :one
+-- Returns the oldest non-terminal (pending/approved/completed) request
+-- whose own-kind MBID matches @mbid, or pgx.ErrNoRows when none. Create()
+-- uses this to dedupe: a re-request for something already in flight
+-- returns the existing row instead of inserting a duplicate. MBIDs are
+-- globally unique per entity type, so the cross-column OR cannot
+-- false-match (an artist MBID never collides with an album/track MBID).
+SELECT * FROM lidarr_requests
+ WHERE status IN ('pending', 'approved', 'completed')
+   AND ((kind = 'artist' AND lidarr_artist_mbid = @mbid)
+     OR (kind = 'album'  AND lidarr_album_mbid  = @mbid)
+     OR (kind = 'track'  AND lidarr_track_mbid  = @mbid))
+ ORDER BY requested_at ASC
+ LIMIT 1;
+
+-- name: MarkLidarrRequestAddConfirmed :exec
+-- Idempotently records that Lidarr accepted the add for an approved
+-- request. The lidarr_add_confirmed_at IS NULL guard makes a redundant
+-- reconciler retry a no-op rather than bumping updated_at every tick.
+UPDATE lidarr_requests
+   SET lidarr_add_confirmed_at = now(),
+       updated_at              = now()
+ WHERE id = $1
+   AND status = 'approved'
+   AND lidarr_add_confirmed_at IS NULL;