Phase 1: Foundation — backend auth, frontend shell, Docker setup

Backend (FastAPI):
- App factory with async SQLAlchemy 2.0 + PostgreSQL
- Alembic migration for users and sessions tables
- JWT auth (access + refresh tokens, bcrypt passwords)
- Auth endpoints: register, login, refresh, logout, me
- Admin seed script, role-based access deps

Frontend (React + TypeScript):
- Vite + Tailwind CSS + shadcn/ui theme (health-oriented palette)
- i18n with English and Russian translations
- Zustand auth/UI stores with localStorage persistence
- Axios client with automatic token refresh on 401
- Login/register pages, protected routing
- App layout: collapsible sidebar, header with theme/language toggles
- Dashboard with placeholder stats

Infrastructure:
- Docker Compose (postgres, backend, frontend, nginx)
- Nginx reverse proxy with WebSocket support
- Dev override with hot reload

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/app/models/user.py

@@ -0,0 +1,27 @@
+from datetime import datetime
+
+from sqlalchemy import Boolean, DateTime, Integer, String, func
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    email: Mapped[str] = mapped_column(String(255), unique=True, index=True, nullable=False)
+    username: Mapped[str] = mapped_column(String(100), unique=True, index=True, nullable=False)
+    hashed_password: Mapped[str] = mapped_column(String(255), nullable=False)
+    full_name: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    role: Mapped[str] = mapped_column(String(20), nullable=False, default="user")
+    is_active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)
+    max_chats: Mapped[int] = mapped_column(Integer, nullable=False, default=10)
+    oauth_provider: Mapped[str | None] = mapped_column(String(50), nullable=True)
+    oauth_provider_id: Mapped[str | None] = mapped_column(String(255), nullable=True)
+    telegram_chat_id: Mapped[int | None] = mapped_column(nullable=True)
+    avatar_url: Mapped[str | None] = mapped_column(String(500), nullable=True)
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), onupdate=func.now(), nullable=False
+    )
+
+    sessions: Mapped[list["Session"]] = relationship(back_populates="user", cascade="all, delete-orphan")  # noqa: F821