Add concurrency control to cancel stale PR workflow runs

[Copilot]

Adds concurrency grouping to the CI workflow to automatically cancel in-progress runs when new commits are pushed to a PR.

Changes

• Added concurrency block to .github/workflows/ci.yml:
  • Groups runs by workflow-name + (PR-branch || git-ref)
  • Enables cancel-in-progress: true

Implementation

concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
  cancel-in-progress: true

For PRs, github.head_ref groups by branch. For push/tag events, github.ref provides the grouping key.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.