docs(spikes): add batch 550-599 design dossiers and verified blockers - #602

The strategy configuration was canceled because "contracts.mock-token" failed

The operation was canceled.

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/