Optimize signal read paths and enforce score invariants

app/models/score.py

@@ -1,6 +1,6 @@
 from datetime import datetime
 
-from sqlalchemy import Boolean, DateTime, Float, ForeignKey, String, Text
+from sqlalchemy import Boolean, DateTime, Float, ForeignKey, String, Text, UniqueConstraint
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 
 from app.database import Base
@@ -8,6 +8,9 @@ from app.database import Base
 
 class DimensionScore(Base):
     __tablename__ = "dimension_scores"
+    __table_args__ = (
+        UniqueConstraint("ticker_id", "dimension", name="uq_dimension_score_ticker_dimension"),
+    )
 
     id: Mapped[int] = mapped_column(primary_key=True)
     ticker_id: Mapped[int] = mapped_column(
@@ -25,6 +28,9 @@ class DimensionScore(Base):
 
 class CompositeScore(Base):
     __tablename__ = "composite_scores"
+    __table_args__ = (
+        UniqueConstraint("ticker_id", name="uq_composite_score_ticker"),
+    )
 
     id: Mapped[int] = mapped_column(primary_key=True)
     ticker_id: Mapped[int] = mapped_column(