Migrate CI to GitHub Actions

[vikram-ecobee]

Summary

• replace the CircleCI pipeline with GitHub Actions
• run cached npm installs, builds, unit tests, coverage uploads, and Codecov reporting
• publish to npm from successful pushes to master using repository secrets
• update the README CI badge

Validation

• npm ci
• npm run build
• npx jest --ci --runInBand --reporters=default --reporters=jest-junit --coverage

[gemini-code-assist]

Code Review

This pull request removes the CircleCI configuration and updates the README to reference a GitHub Actions CI badge. However, the corresponding GitHub Actions workflow file (.github/workflows/ci.yml) is missing from the pull request and must be added to complete the migration.

[gemini-code-assist]

The GitHub Actions workflow file (.github/workflows/ci.yml) referenced by this badge is missing from the pull request. Please add the workflow file to complete the migration from CircleCI to GitHub Actions.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (6cadfa3) to head (4d16fb5).

Additional details and impacted files

@@            Coverage Diff            @@
##            master       #49   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines           73        82    +9     
  Branches         9         9           
=========================================
+ Hits            73        82    +9     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.