Add CI quality gate workflow

[revsmoke]

Summary

Adds a GitHub Actions CI workflow to enforce repository quality gates.

Changes

• Add .github/workflows/ci.yml
• Run on pull_request and push to main
• Steps:
  • checkout
  • setup bun
  • bun install --frozen-lockfile
  • bun run typecheck
  • bun test --coverage
  • upload coverage-summary.txt artifact

Validation

• Local bun run typecheck passes
• Local bun test passes

Summary by CodeRabbit

• Chores
  • Added automated continuous integration workflow for code validation and testing.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

Introduces a GitHub Actions CI workflow that automates code quality checks and testing. The workflow triggers on pull requests and pushes to main, running type checking, tests with coverage reporting, and uploading coverage summaries as artifacts.

Changes

Cohort / File(s)	Summary
GitHub Actions CI Configuration .github/workflows/ci.yml	New workflow file that defines a CI pipeline running on ubuntu-latest. Includes steps for code checkout, Bun setup, dependency installation with frozen lockfile, type checking, test execution with coverage reporting, and coverage artifact upload.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Poem

🐰 A workflow takes shape, so tidy and bright,
With tests that will run through the day and the night,
Coverage tracked like carrots in rows,
CI checking our code as it grows!

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch codex/p2-ci-gate

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