On native Windows, Claude Code runs each hook as `bash.exe -c "<command>"`
through the Windows command line. That extra unescape layer collapses the
backslashes in the WSL path conversion of the inline plugin-root resolver,
so `.replace(/\\/g,'/')` reaches node as `.replace(/\/g,'/')` and every hook
fails with `SyntaxError: missing ) after argument list`.
Build the backslash separator with String.fromCharCode(92) and split/join
instead of regex escapes, so the resolver contains no backslash. Conversion
behaviour is unchanged. Regenerate every embedded copy (hooks.json,
codex-hooks.json, commands/*.md) and refresh hooks.metadata.json
fingerprints.
Add a test that the resolver and each hook `node -e` program are
backslash-free, and run the shipped SessionStart command through bash with
backslashes collapsed the way Windows does.
Fixes#3746