ci: add E2E tests to GitHub Actions pipeline

[hartym]

Summary

The GitHub Actions workflow runs backend and frontend unit tests but does not run E2E tests. The entire prod-mode bundle serving path is untested in CI.

Current state

• make test-all exists and runs core + E2E tests
• E2E infrastructure is mature (14 Playwright projects, parallel setup)
• CI only runs test-backend and test-frontend jobs

Proposed solution

Add a test-e2e job to .github/workflows/cicd.yml that:

1. Sets up all 7 example apps
2. Runs make test-e2e (or at minimum make test-e2e-dev)
3. Uses Playwright GitHub Action for browser installation
4. Uploads test artifacts on failure

[m13v]

with 14 Playwright projects, the CI job setup is going to be the tricky part. running all projects in parallel eats a lot of CI minutes and can cause flakiness from resource contention. what worked for us: shard the tests across multiple CI matrix jobs using Playwright's built-in sharding (--shard=1/4, --shard=2/4 etc). that way each job runs a subset and the total wall time stays reasonable. for the example apps setup, make sure the server startup is properly awaited before tests begin. Playwright's webServer config handles this but with 7 apps you might want a custom health check script instead. also upload the HTML report as an artifact even on success, not just failure, so you can track test duration trends.

[m13v]

for the parallel browser management in CI (preventing test conflicts when sharding), we use this lock-based orchestration: https://github.com/m13v/browser-lock/blob/main/playwright-lock.sh

[hartym]

Thanks for the info, not sure yet whether this will be a problem or not. Will keep in mind when implementing.