Eliminate all code paths, configuration, and documentation related to running
without authentication. Require AUTH_SECRET and BASE_URL at startup, updating
middleware, server logic, and runtime checks to assume auth is always enabled.
Simplify onboarding, settings, and test helpers to reflect mandatory auth.
Update environment examples, Docker and deployment docs, and CI/test configs.
Remove no-auth-specific UI flows, test cases, and feature toggles.
Add Next.js middleware to handle session-based access control for protected
routes while maintaining access to public paths. Configure comprehensive
security headers including CSP, HSTS, and frame options in next.config.ts.
Also, reduce session cookie cache duration to 5 minutes to ensure frequent
revalidation against the database and fix a navigation issue in the EPUB
context when jumping to specific CFI locations.
