fix: bind HWID top-ups to subscription periods

backend/db/models.py

@@ -203,6 +203,11 @@ class Payment(Base):
     tariff_key = Column(String, nullable=True, index=True)
     purchased_gb = Column(Float, nullable=True)
     purchased_hwid_devices = Column(Integer, nullable=True)
+    hwid_valid_from = Column(DateTime(timezone=True), nullable=True)
+    hwid_valid_until = Column(DateTime(timezone=True), nullable=True)
+    hwid_pricing_period_months = Column(Integer, nullable=True)
+    hwid_proration_ratio = Column(Float, nullable=True)
+    hwid_full_price = Column(Float, nullable=True)
     promo_code_id = Column(Integer, ForeignKey("promo_codes.promo_code_id"), nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), onupdate=func.now(), nullable=True)
@@ -229,6 +234,14 @@ class TrafficTopup(Base):
 
 class HwidDevicePurchase(Base):
     __tablename__ = "hwid_device_purchases"
+    __table_args__ = (
+        Index(
+            "ix_hwid_device_purchases_subscription_window",
+            "subscription_id",
+            "valid_from",
+            "valid_until",
+        ),
+    )
 
     purchase_id = Column(Integer, primary_key=True, autoincrement=True)
     subscription_id = Column(
@@ -236,6 +249,8 @@ class HwidDevicePurchase(Base):
     )
     payment_id = Column(Integer, ForeignKey("payments.payment_id"), nullable=True, index=True)
     purchased_devices = Column(Integer, nullable=False)
+    valid_from = Column(DateTime(timezone=True), nullable=True)
+    valid_until = Column(DateTime(timezone=True), nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())
 
     subscription = relationship("Subscription")
@@ -276,6 +291,8 @@ class TariffChange(Base):
     days_before = Column(Integer, nullable=True)
     days_after = Column(Integer, nullable=True)
     converted_bytes = Column(BigInteger, nullable=True)
+    converted_hwid_value_rub = Column(Numeric, nullable=True)
+    converted_hwid_days = Column(Integer, nullable=True)
     eff_price_before = Column(Numeric, nullable=True)
     eff_price_after = Column(Numeric, nullable=True)
     created_at = Column(DateTime(timezone=True), server_default=func.now())