feat(subsonic): wire contextual_likes capture/soft-delete into star/unstar

handleStar's track branch calls playevents.CaptureContextualLikeIfPlaying
when the underlying LikeTrack actually inserted a row. handleUnstar
calls SoftDeleteContextualLikes after every track-id unstar. Same
helpers as the api surface — single source of truth.

mediaHandlers struct gains a logger field threaded through Mount.

internal/subsonic/subsonic.go

@@ -21,7 +21,7 @@ import (
 // either way.
 func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, cfg Config, events *playevents.Writer) {
 	b := &browseHandlers{pool: pool}
-	m := newMediaHandlers(pool, events)
+	m := newMediaHandlers(pool, events, logger)
 	r.Route("/rest", func(sub chi.Router) {
 		sub.Use(Middleware(pool, cfg))
 		register(sub, "/ping", handlePing)
@@ -52,7 +52,6 @@ func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, cfg Config, ev
 		sub.NotFound(func(w http.ResponseWriter, r *http.Request) {
 			WriteFail(w, r, ErrGeneric, "Method not implemented")
 		})
-		_ = logger
 	})
 }