Extract shared test runner (helpers.js), add file-based SQLite with
setup_db.py for fixture seeding, and add tests for auth guard, credentials
management, full registration flow, health endpoint, password auth, and
magic link registration errors. 66 checks across 7 test files.
Set up tests/e2e/ with a login page test covering branding, accessibility,
form structure, theme colors, and static asset serving. Includes run.sh
that manages the app lifecycle (start, test, stop) automatically.