Install Evergreen PR health workflow

[Copilot]

New Feature

Evergreen keeps PRs healthy by periodically merging main, fixing CI failures, and triggering missing CI on Autoloop PRs. This installs the workflow for tsikit-learn.

• Workflow

  • Added .github/workflows/evergreen.md adapted from githubnext/tsessebe.
  • Added compiled .github/workflows/evergreen.lock.yml.

• tsikit-learn adaptation

  • Kept node and added python to the network allow list.
  • References GH_AW_CI_TRIGGER_TOKEN.
  • Dispatches this repo’s CI workflow via ci.yml.

workflow_file = "ci.yml"
url = f"https://api.github.com/repos/{repo}/actions/workflows/{workflow_file}/dispatches"
payload = json.dumps({"ref": branch}).encode()

• CI trigger support
  • Added workflow_dispatch to .github/workflows/ci.yml so Evergreen can trigger CI directly.