App e2e tests

Read packages/app/e2e/AGENTS.md and the Tests section of packages/app/AGENTS.md first. They define what to test, which locators to use, and how to assert. packages/app/README.md (E2E Testing) documents run modes and env vars. This skill covers what makes these tests slow or flaky in CI, which runs the suite as two shards per OS on 4-vCPU runners (.github/workflows/check-test.yml:217-240). Most races below were found on Windows.

All paths below are relative to packages/app unless they start with packages/, services/ or .github/.

What a test runs against