When installing the LaunchAgent/systemd service, the CLI was using
fs.realpath() to resolve the entry.js path, which converted stable
symlinked paths (e.g. node_modules/clawdbot) into version-specific
paths (e.g. .pnpm/clawdbot@X.Y.Z/...).
This caused the service to break after pnpm updates because the old
versioned path no longer exists, even though the symlink still works.
Now we prefer the original (symlinked) path when it's valid, keeping
service configs stable across package version updates.
