macOS ships /bin/bash 3.2.57 which has no `${var,,}` parameter expansion.
Replace with a portable case statement matching y/Y. Behaviorally
identical (read -n 1 already constrains input to a single char, and the
original code only accepted 'y' after lowercasing, so 'y' and 'Y' are
the only accepting inputs).
Repo-wide audit for other bash 4+ features (case modification, mapfile,
nameref locals, ${var@op} transforms, coproc) returned clean.
Repro before fix:
$ ./install.sh
Enable daily scheduled sync (launchd)? [y/N]: y
lib/common.sh: line 52: ${reply,,}: bad substitution
Co-authored-by: Cursor <cursoragent@cursor.com>
Oliver Surke
69541209dc