feat: add SQLAlchemy models for Category, CategoryWord, Game, Word

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

models/category.py

@@ -0,0 +1,24 @@
+from sqlalchemy import Column, ForeignKey, Integer, String, UniqueConstraint
+from sqlalchemy.orm import relationship
+
+from models import Base
+
+
+class Category(Base):
+    __tablename__ = "categories"
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    name = Column(String(50), unique=True, nullable=False)
+
+    words = relationship("CategoryWord", back_populates="category")
+
+
+class CategoryWord(Base):
+    __tablename__ = "category_words"
+    __table_args__ = (UniqueConstraint("category_id", "word"),)
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    category_id = Column(Integer, ForeignKey("categories.id"), nullable=False)
+    word = Column(String(20), nullable=False)
+
+    category = relationship("Category", back_populates="words")