Initial project scaffold

Full-stack homeschool web app with FastAPI backend, Vue 3 frontend,
MySQL database, and Docker Compose orchestration. Includes JWT auth,
WebSocket real-time TV dashboard, schedule builder, activity logging,
and multi-child support.

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

backend/app/models/subject.py

@@ -0,0 +1,22 @@
+from sqlalchemy import String, Boolean, ForeignKey
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from app.models.base import Base, TimestampMixin
+
+
+class Subject(TimestampMixin, Base):
+    __tablename__ = "subjects"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), nullable=False)
+    name: Mapped[str] = mapped_column(String(100), nullable=False)
+    color: Mapped[str] = mapped_column(String(7), default="#10B981")  # hex color
+    icon: Mapped[str] = mapped_column(String(10), default="📚")       # emoji
+    is_active: Mapped[bool] = mapped_column(Boolean, default=True)
+
+    user: Mapped["User"] = relationship("User", back_populates="subjects")  # noqa: F821
+    schedule_blocks: Mapped[list["ScheduleBlock"]] = relationship(  # noqa: F821
+        "ScheduleBlock", back_populates="subject"
+    )
+    activity_logs: Mapped[list["ActivityLog"]] = relationship(  # noqa: F821
+        "ActivityLog", back_populates="subject"
+    )