The runtime --sandbox-allow CLI override path never expanded the supported
sandbox variables (${CWD}, ${HOME}, ${TMPDIR}), so a value like
write='${CWD}/**' was treated as a literal path segment and the allow rule
never matched. Profile-loaded sandbox paths already expand these via
sandbox/util.ExpandVariables.
Expand the variables in resolveToAbsolute, the shared chokepoint for
read/write/exec overrides, before resolving to an absolute path. Glob
characters are preserved through expansion and filepath.Clean.
Fixes#257
Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
