구조적인 부분 수정

backend/app/models/models.py

@@ -178,11 +178,14 @@ class MCPToolCall(Base):
 class StockAnalysis(Base):
     """매일 배치로 저장되는 종목 분석 데이터"""
     __tablename__ = "stock_analysis"
-    
+    __table_args__ = (
+        UniqueConstraint("stock_code", "analysis_date", name="uq_stock_analysis_code_date"),
+    )
+
     id = Column(Integer, primary_key=True, index=True)
     stock_code = Column(String(20), nullable=False, index=True)
     stock_name = Column(String(100), nullable=False)
-    analysis_date = Column(DateTime, nullable=False, index=True)
+    analysis_date = Column(Date, nullable=False, index=True)
     
     # 가격 정보
     current_price = Column(Integer, nullable=False)