In bash, strings cannot contain NUL bytes, so `$'\0'` expands to the empty
string. The pattern `*$'\0'*` collapsed to `**`, which matches every
non-empty value, so `validate_path` aborted on every real path with
"Path contains control chars".
- Drop the NUL check entirely (impossible to violate by construction).
- Use a single case statement for the newline and traversal checks; more
predictable than chained [[ ... && ... ]] glob comparisons on bash 3.2.
Verified: paths with spaces, dots in basenames (~/.config, ~/.local), and
the iCloud bundle directory all pass; empty paths, "..", and embedded
newlines still reject.
Repro before fix:
$ ./install.sh
[ERR] Path contains control chars
Co-authored-by: Cursor <cursoragent@cursor.com>
Oliver Surke