Optimize signal read paths and enforce score invariants

app/models/sr_level.py

@@ -1,6 +1,6 @@
 from datetime import datetime
 
-from sqlalchemy import DateTime, Float, ForeignKey, Integer, String
+from sqlalchemy import DateTime, Float, ForeignKey, Index, Integer, String
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from app.database import Base
@@ -8,6 +8,7 @@ from app.database import Base
 
 class SRLevel(Base):
     __tablename__ = "sr_levels"
+    __table_args__ = (Index("ix_sr_levels_ticker_id", "ticker_id"),)
 
     id: Mapped[int] = mapped_column(primary_key=True)
     ticker_id: Mapped[int] = mapped_column(