feat(auth): include expires_at in token responses and KeyPair DTO

db/models/pricing.py

@@ -0,0 +1,19 @@
+from datetime import datetime
+
+from sqlalchemy import FLOAT, INTEGER, TIMESTAMP, CheckConstraint, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from db.base import Base
+
+
+class PricingConfig(Base):
+    __tablename__ = "pricing_configs"
+
+    __table_args__ = (
+        CheckConstraint("id = 1", name="single_row_check"),
+    )
+
+    id: Mapped[int] = mapped_column(INTEGER, autoincrement=True, unique=True, nullable=False, primary_key=True)
+    device_price: Mapped[float] = mapped_column(FLOAT, nullable=False)
+
+    updated_at: Mapped[datetime] = mapped_column(TIMESTAMP, server_default=func.now(), onupdate=func.now())