add: SQLite-backed structured logging with retention

Replace JSON/file logging with a logs.db (WAL) store. Thread the logger
through the encoder and metadata client for debug instrumentation of every
ffmpeg/ffprobe/opusenc invocation and OMDb/TVmaze request. API keys are
redacted before request URLs are logged. Retention defaults to 7 days,
overridable via log_retention_days in config.

cmd/videnc/main.go

@@ -46,21 +46,21 @@ func main() {
 		os.Exit(1)
 	}
 
-	log, err := logger.New(".")
+	log, err := logger.New(".", cfg.LogRetentionDays)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to initialize logger: %v\n", err)
 		os.Exit(1)
 	}
 	defer log.Close()
 
-	enc := encoder.New()
+	enc := encoder.New(log)
 	if err := enc.CheckDeps(); err != nil {
 		log.Error("Dependency check failed", err.Error())
 		fmt.Fprintf(os.Stderr, "Dependency check failed: %v\n", err)
 		os.Exit(1)
 	}
 
-	metaClient := metadata.NewClient(cfg.OMDBAPIKey)
+	metaClient := metadata.NewClient(cfg.OMDBAPIKey, log)
 
 	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
 	defer cancel()
@@ -128,11 +128,15 @@ func processFile(ctx context.Context, inputPath string, cfg *types.Config, enc *
 		meta, err = metaClient.FetchSeriesMetadata(ctx, tvmazeID, season, episode)
 		if err != nil {
 			log.ErrorFile(inputPath, "Fetching series metadata", err.Error())
+		} else if meta != nil {
+			log.Info(fmt.Sprintf("TVmaze hit: %s S%sE%s - %s", meta.Collection, meta.Season, meta.Episode, meta.Title))
 		}
 	} else if imdbID != "" {
 		meta, err = metaClient.FetchMovieMetadata(ctx, imdbID)
 		if err != nil {
 			log.ErrorFile(inputPath, "Fetching movie metadata", err.Error())
+		} else if meta != nil {
+			log.Info(fmt.Sprintf("OMDb hit: %s (%s)", meta.Title, meta.IMDBID))
 		}
 	}