Spec for adding username+password auth to the WebUI to close the
unauthenticated-API exposure (all /api/* and /ws currently open).
Design: SQLite users + sessions tables, bcryptjs, 7-day rolling
HTTP-only cookie sessions, first-run setup wizard, Origin/Referer
CSRF check, WebSocket upgrade gated on the same session cookie.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
