Install CI Doctor agentic workflow

[Copilot]

New Feature

Installs the CI Doctor agentic workflow from githubnext/agentics.

What does this feature do?

Adds an automated CI failure investigator that triggers on workflow_run completion of the monitored workflow, analyzes logs and root causes, and opens an investigation issue (label: automation, ci, title prefix [ci-doctor]) with findings and recommended fixes.

Implementation details

• gh aw add githubnext/agentics/ci-doctor — adds the source workflow at .github/workflows/ci-doctor.md.
• Monitored workflow retargeted to this repo's CI. Upstream defaults reference workflows that don't exist here:

  on:
    workflow_run:
      workflows: ["CI"]   # was: ["Daily Perf Improver", "Daily Test Coverage Improver"]

• gh aw compile regenerates .github/workflows/ci-doctor.lock.yml (the executed YAML).
• .github/aw/actions-lock.json left untouched — gh aw would have pruned github/gh-aw-actions/setup@v0.72.1, but it is still referenced by the existing autoloop / evergreen lock files (compiled with a newer gh-aw than the one in this sandbox).

Follow-ups for reviewers

• Confirm CI is the right workflow to monitor, or extend the list (e.g. add Autoloop, Evergreen — PR Health Keeper, Deploy Playground to Pages).
• Recompiling with the same gh-aw version used for the other lock files (v0.72.1) would produce a lock file consistent with the rest of the repo; the v0.71.1 output committed here is functionally equivalent but uses older pinned action SHAs.