Align CI fixer and feedback evals with GitHub MCP policies

[vitek-karas]

Problem

The production ci-failure-fix and ci-failure-scan-feedback workflows require issue, pull request, and comment content to be read through the integrity-gated GitHub MCP tools. Their Vally eval stimuli and tool-call graders still instruct and reward shell gh reads instead.

This means /ci-fix eval and /ci-feedback eval exercise a different retrieval path than production and can pass without validating the workflows' MCP-only content-read policies. This mismatch surfaced while updating the shared MCP authentication plumbing in #132619; that PR intentionally aligns only the ci-failure-scan eval.

Proposed work

• Update the fixer eval stimulus to discover KBEs with scoped search_issues calls and read issue bodies/comments with issue_read.
• Update the feedback eval stimulus to use scoped search_issues and search_pull_requests, then read issue/PR bodies and comments through issue_read and pull_request_read.
• Retain shell gh only for workflow metadata and repository-owned artifact enumeration explicitly permitted by each production prompt.
• Update tool-call graders to require the canonical github-* MCP calls and reject shell-based GitHub content reads.
• Run the Docker-backed live evals to confirm both workflows satisfy the updated contracts.
• Update .github/workflows/evals/README.md to describe the MCP-backed behavior accurately.

Note

This issue was created with GitHub Copilot.

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/runtime-infrastructure
See info in area-owners.md if you want to be subscribed.