feat: add User model and Alembic migration for users table

app/modules/auth/models.py

@@ -0,0 +1,29 @@
+from datetime import datetime
+
+from sqlalchemy import Boolean, DateTime, Integer, String
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.sql import func
+
+from app.core.database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
+    username: Mapped[str] = mapped_column(String(64), unique=True, nullable=False, index=True)
+    full_name: Mapped[str] = mapped_column(String(128), nullable=False, default="")
+    email: Mapped[str | None] = mapped_column(String(128), nullable=True)
+    department: Mapped[str | None] = mapped_column(String(64), nullable=True)
+    role: Mapped[str | None] = mapped_column(String(64), nullable=True)
+    pw_hash: Mapped[str | None] = mapped_column(String(256), nullable=True)
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
+    is_admin: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+    account_expires: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    last_login: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime, server_default=func.now(), nullable=False
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime, server_default=func.now(), onupdate=func.now(), nullable=False
+    )