Feature/lab3

[BearAx]

Goal

Complete Lab 3 by adding a PR-gated GitHub Actions pipeline for QuickNotes with vet, race tests, linting, caching, matrix builds, path filters, and branch-protection evidence.

Changes

• Added .github/workflows/ci.yml
• Configured CI to run on pushes to main and pull requests targeting main
• Added separate CI jobs for:
  • go vet ./...
  • go test -race -count=1 ./...
  • golangci-lint run
• Pinned the runner to ubuntu-24.04
• Pinned GitHub Actions by full commit SHA
• Added least-privilege workflow permissions with contents: read
• Added Go module/build caching through actions/setup-go
• Added Go version matrix for 1.23.x and 1.24.x
• Added ci-ok aggregation job for stable branch-protection checks
• Added path filters for app/** and .github/workflows/ci.yml
• Added submissions/lab3.md with required evidence and design-question answers

Testing

• Confirmed the CI pipeline runs successfully on the Lab 3 PR
• Verified vet, test, and lint jobs pass
• Created an intentional failing test to confirm the PR gate turns red
• Removed the intentional failure and confirmed CI returned green
• Verified branch protection requires the ci-ok status check
• Checked that docs-only changes are skipped by the workflow path filter
• Collected CI timing data for baseline, cache, and cache + matrix scenarios

Checklist

• Title is a clear sentence
• Commits are signed
• .github/workflows/ci.yml added
• submissions/lab3.md updated
• CI runs vet, test, and lint
• Runtime environment is pinned
• GitHub Actions are pinned by SHA
• permissions: is configured
• Cache is enabled
• Go matrix is configured
• Path filters are configured
• Branch protection evidence included
• Failure and fix evidence included