fix(release,darkauth-client): stabilize publish workflow version handling

[markwylde]

Summary

• remove the client_version output step that used nested shell quoting and failed in GitHub Actions
• reuse the already-resolved semantic-release version (release_version) for the npm publish existence check
• keep client version alignment behavior unchanged (npm version <semantic-release-version> -w @darkauth/client)

Why this fixes the failure

• the failed step was parsing version text with nested command substitution/escaping
• using release_version avoids shell-escaping pitfalls entirely and uses the same version source already used to set the package version

Validation

• npm run tidy
• npm run build