Uses \$'...' quoting for spinner backslash (SC1003). Adds source=/dev/null
for /etc/os-release (SC1091). Splits local+assign for ip and
current_version (SC2155). Adds disable comments for intentional literal
regex matches (SC2076).
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
