[Fix] Fast mode cannot explain GitHub Actions failures

[roomote-roomote]

​Opened on behalf of @daniel-lxs. Follow up by mentioning @roomote-roomote or in the web UI.

What changed

• Added the upstream GitHub MCP actions toolset to Fast mode's existing read-only GitHub proxy.
• Allowlisted only actions_get, actions_list, and get_job_logs; mutating Actions tools remain unavailable.
• Added focused policy and broker tests proving the three tools are exposed to Fast mode.

Why this change was made

Fast mode already uses the deployment GitHub App through a read-only MCP policy, but the policy filtered out Actions inspection tools. The existing GitHub App manifest already requests Actions access, so no permission UI, redirect flow, documentation, or prompt guidance is needed for this change.

Impact

Fast mode can inspect GitHub Actions runs, jobs, and logs without gaining workflow mutation capabilities. Targeted tests, type checks, changed-file lint and formatting checks, and the repository pre-push suite pass; the broader cloud-agents ESLint command still reports unrelated pre-existing warnings outside this diff.

[roomote-community]

No new code issues found. See task

_{Reviewed e7d64fe}