Two pre-existing harness breaks found while running the device tests:
- RegisterRoutes dereferences cfg.Settings (auth rate limit) but
setupTestServer never set it — every integration test nil-panicked at
route registration. Wire database.NewSettingsRegistry(queries) the
same way main.go does.
- The cleanup deliberately PRESERVES testuser@tests.bookhoard.internal
(shared dev admin), but setup then blindly re-INSERTed that user, so
every run after the first failed on users_email_key. Reuse the user
when it exists; default collections are created only for a NEW user
(the preserved admin already has its set).
Also documented the offline runner used on slow links: build the test
binary on the host (CGO_ENABLED=0 go test -c) and execute it inside the
bookhoard-tests image against the compose network — no in-container
module downloads, no image rebuild.