Standardise an opt-in SSE progress-streaming response for /evaluate and /chat - #44

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, actions/setup-node@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

Example value must conform to the schema: must NOT have unevaluated properties `capabilities`.

Example value must conform to the schema: must NOT have unevaluated properties `version`.

Example value must conform to the schema: must NOT have unevaluated properties `capabilities`.

Example value must conform to the schema: must NOT have unevaluated properties `version`.

Example value must conform to the schema: must NOT have unevaluated properties `status`.

Example value must conform to the schema: `1` property must NOT have unevaluated properties `maxPoints`.

Example value must conform to the schema: `0` property must NOT have unevaluated properties `maxPoints`.