fix: address code review findings

internal/scanner/scan.go

@@ -2,6 +2,7 @@ package scanner
 
 import (
 	"context"
+	"log"
 
 	"naviwatcher/internal/database"
 )
@@ -55,9 +56,12 @@ func ScanAll(ctx context.Context, db *database.DB, threshold float64) ([]Missing
 		if !s.Monitored {
 			continue
 		}
+		// A transient error for one artist must not abort the whole scan and
+		// take down the daemon; log it and continue with the remaining artists.
 		missing, err := ScanArtist(ctx, db, s.ID, resolved)
 		if err != nil {
-			return all, err
+			log.Printf("scan artist %s failed: %v", s.ID, err)
+			continue
 		}
 		all = append(all, missing...)
 	}