User-specific path regressions corrected.

Such regressions centralized on string global ${ZESHY_USER_DIR_STACK_FILE}
initialized formerly by startup_zeshy_paths() and now by @{main}. While the
exact cause of such regression remains unclear (which itself is somewhat
concerning), such correction *APPEARS* to adequately address the issue.

Mysteries abound in the boundless codebase.