Adding ability to update / patch by sku, adding uniqueness constraint violation checks

app/models/augmented_part.py

@@ -17,7 +17,9 @@ class AugmentedPart(Base):
     __tablename__ = "augmented_parts"
 
     id: Mapped[int] = mapped_column(primary_key=True)
-    sku: Mapped[str | None] = mapped_column(String, nullable=True, default=None)
+    sku: Mapped[str | None] = mapped_column(
+        String, nullable=True, unique=True, default=None
+    )
     description: Mapped[str] = mapped_column(String, nullable=False)
     colour_id: Mapped[int] = mapped_column(
         ForeignKey("part_colours.id", ondelete="RESTRICT"), nullable=False