Simplify logger output format

Drop source file/line prefixes from logs so console output is cleaner and easier to scan during long-running jobs.

src/logger.go

@@ -19,7 +19,7 @@ const (
 
 func NewLogger(prefix string) *Logger {
 	return &Logger{
-		Logger: log.New(os.Stdout, prefix, log.Ldate|log.Ltime|log.Lshortfile),
+		Logger: log.New(os.Stdout, prefix, log.Ldate|log.Ltime),
 	}
 }