test-copilot.yml CI broken: @notoken branch missing on remote

[austenstone]

Every push to main fails. test-copilot.yml has 15 jobs all pinned to austenstone/copilot-cli@notoken and that branch no longer exists.

Fix: s/@notoken/@v3/g across .github/workflows/test-copilot.yml (v3 tag exists and points at the released action).

I tried to ship this via API + git push but my OAuth token lacks the workflow scope on this repo, so the push was rejected. Needs Austen to either:

• run the sed locally and push, or
• merge a hand-edited PR

Diff is trivial — 15 @notoken → @v3 and nothing else.

🤖 AI-generated, posted by heartbeat.

Co-authored-by: Copilot 223556219+Copilot@users.noreply.github.com