Add initial project files

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/models/user.py

@@ -0,0 +1,19 @@
+from datetime import datetime
+from typing import Optional
+from sqlalchemy import String, DateTime, func
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    email: Mapped[str] = mapped_column(String(255), unique=True, nullable=False, index=True)
+    password_hash: Mapped[str] = mapped_column(String(255), nullable=False)
+    display_name: Mapped[Optional[str]] = mapped_column(String(100))
+    timezone: Mapped[str] = mapped_column(String(50), default="UTC")
+    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=func.now())
+
+    entries: Mapped[list["Entry"]] = relationship("Entry", back_populates="user", cascade="all, delete-orphan")