Playwright browser suites, marker `e2e`, driven through the `live_server` and
`context`/`page` fixtures in `tests/e2e/conftest.py`.

Naming contract (guarded by `tests/unit/test_harness.py`):

- A **story suite** is named for its story: `test_usNN_*.py`.
- A **technical suite** guards a phase's machinery rather than a single user
  story (e.g. `test_atlas_loads.py`, the phase-07 art/atlas guard, named by
  the phase's task file). Technical suites are an explicit, documented
  exception: they are listed in `E2E_TECHNICAL_SUITES` in `test_harness.py`
  before they may exist.