Phase 1: auth, room CRUD, WebSocket chat, PWA frontend

Invite-only FastAPI + SQLAlchemy(async) + Postgres backend (session-cookie
auth via CLI-provisioned accounts, open-room CRUD, single-instance /ws/chat)
and a React + Vite PWA frontend (login, room list, chat view). Backend tests
pass against a local Postgres DB. See README.md and backend/README.md for
setup, and ARCHITECTURE.md for the full phased design.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/models/__init__.py

@@ -0,0 +1,7 @@
+from app.models.base import Base
+from app.models.membership import RoomMembership, RoomRole
+from app.models.message import Message
+from app.models.room import Room
+from app.models.user import User
+
+__all__ = ["Base", "User", "Room", "RoomMembership", "RoomRole", "Message"]