feat(subsonic): wire /rest/scrobble into playevents.Writer

submission=false → play_started (replaces in-memory nowPlayingMap).
submission=true (default) → synthetic completed play. The nowPlayingMap
struct + factory + the nowPlaying field on mediaHandlers are deleted;
play_events WHERE ended_at IS NULL is now the source of truth for
'currently playing,' reachable from M3+ work.

api.Mount now takes the shared *playevents.Writer instead of cfg so
the same writer instance feeds both surfaces.

internal/api/api.go

@@ -6,26 +6,19 @@ package api
 
 import (
 	"log/slog"
-	"time"
 
 	"github.com/go-chi/chi/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 
 	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
-	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/playevents"
 )
 
 // Mount attaches /api/* handlers to r. Public endpoints (login) are outside
-// RequireUser; everything else is gated by the middleware.
-func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, cfg config.EventsConfig) {
-	w := playevents.NewWriter(
-		pool, logger,
-		time.Duration(cfg.SessionTimeoutMinutes)*time.Minute,
-		cfg.SkipMaxCompletionRatio,
-		cfg.SkipMaxDurationPlayedMs,
-	)
-	h := &handlers{pool: pool, logger: logger, events: w}
+// RequireUser; everything else is gated by the middleware. The events writer
+// is shared with the Subsonic mount so /rest/scrobble feeds the same store.
+func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playevents.Writer) {
+	h := &handlers{pool: pool, logger: logger, events: events}
 
 	r.Route("/api", func(api chi.Router) {
 		api.Post("/auth/login", h.handleLogin)