Update admin theme/layout and refresh README details.

Align the project baseline with the latest admin interface styling and layout structure while documenting setup and usage updates in README.

apps/api/app/modules/users/models.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from uuid import uuid4
+
+from sqlalchemy import DateTime, ForeignKey, Integer, String, Text
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.db.base import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=lambda: str(uuid4()))
+    email: Mapped[str] = mapped_column(String(255), unique=True, nullable=False, index=True)
+    password_hash: Mapped[str] = mapped_column(String(255), nullable=False)
+    role: Mapped[str] = mapped_column(String(16), nullable=False, default="user")
+    is_superuser: Mapped[bool] = mapped_column(nullable=False, default=False)
+    status: Mapped[str] = mapped_column(String(16), nullable=False, default="pending", index=True)
+    failed_login_attempts: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    locked_until: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    email_verified_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=lambda: datetime.now(UTC)
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True),
+        nullable=False,
+        default=lambda: datetime.now(UTC),
+        onupdate=lambda: datetime.now(UTC),
+    )
+
+    profile: Mapped["UserProfile"] = relationship(
+        back_populates="user",
+        uselist=False,
+        cascade="all, delete-orphan",
+        passive_deletes=True,
+    )
+
+
+class UserProfile(Base):
+    __tablename__ = "user_profiles"
+
+    user_id: Mapped[str] = mapped_column(
+        String(36), ForeignKey("users.id", ondelete="CASCADE"), primary_key=True
+    )
+    display_name: Mapped[str] = mapped_column(String(120), nullable=False)
+    avatar_url: Mapped[str | None] = mapped_column(String(512), nullable=True)
+    metadata_json: Mapped[str | None] = mapped_column(Text, nullable=True)
+
+    user: Mapped[User] = relationship(back_populates="profile")