v0.2.0: adversarial hardening — uniform rejection contract across all 7 lineages - #1

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: dlang-community/setup-dlang@d7d85fcde7c4cd5f9a6618fce1bccc316e1e910b. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/