Ci add missing node version spec to enforce consistency with package.json

[clintjeff2]

Motivation

• The repository declared @types/node: "^22" and is tested locally with Node 22, but CI used Node 20 which caused install/test mismatches and CI failures.
• Documenting and enforcing the Node runtime prevents future CI failures and ensures contributors use the correct Node version.

Description

• Add engines.node: ">=22.0.0" to package.json to declare the required Node runtime.
• Update .github/workflows/ci.yml to use node-version: 22 for the CI setup-node step.
• Add .nvmrc with 22 so nvm users pick Node 22 automatically.
• Add .node-version with 22 for tools that read that file (Volta, nodenv, etc.).

Testing

• Ran a quick verification script node -e "..." that checks package.json.engines.node, .nvmrc, .node-version, and that the CI workflow contains node-version: 22, and it exited successfully.
• Ran git diff --check and found no whitespace or diff issues.

---

Closes #224

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[clintjeff2]

@leocagli, review and merge.