epwshiftr_cli() is the package-level entry point used by the optional
epwshiftr launcher. It exposes ESGF store operations, weather-method
discovery, and persistent single-run or batch future-weather workflows, and
returns status metadata when exit = FALSE, which makes it testable from R.
epwshiftr_cli(args = commandArgs(trailingOnly = TRUE), exit = FALSE)Invisibly, a list with status, result, and error.