v0.5.1

Fixed

• macOS mktemp compatibility: BSD mktemp does not allow characters after the XXXXXX template suffix — moved XXXXXX to end of all templates and use ${TMPDIR:-/tmp} for portable temp directory resolution
• Bash 3.2 unbound variable crash: empty array expansion under set -u fails on macOS default bash — build argv incrementally with length checks in ypi launcher

Fixes #1, fixes #2