ci: improve Node/tooling guardrails and add zizmor workflow scan

[thi-bot]

Summary

• update CI cache action from actions/cache@v3 to actions/cache@v4
• declare supported runtime with engines in package.json (node >=22 <23, npm >=10)
• add a dedicated zizmor GitHub Actions workflow to statically analyze workflow security

Why

• keeps CI dependencies current
• makes local and CI Node expectations explicit
• adds proactive GitHub Actions security checks without touching React/Draft.js runtime dependencies

Validation

• npm run lint
• npm run test:ci

[github-advanced-security]

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