fix finance balance delta recharges

backend/app/models/upstream_recharge_event.py

@@ -0,0 +1,24 @@
+from datetime import date, datetime, timezone
+
+from sqlalchemy import Date, DateTime, Float, ForeignKey, Index, Integer, String, Text
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.database import Base
+
+
+class UpstreamRechargeEvent(Base):
+    __tablename__ = "upstream_recharge_events"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
+    upstream_id: Mapped[int] = mapped_column(Integer, ForeignKey("upstreams.id", ondelete="CASCADE"), index=True)
+    recharge_date: Mapped[date] = mapped_column(Date, nullable=False)
+    amount: Mapped[float] = mapped_column(Float, nullable=False)
+    note: Mapped[str] = mapped_column(Text, default="")
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=lambda: datetime.now(timezone.utc))
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc)
+    )
+
+    __table_args__ = (
+        Index("ix_recharge_upstream_date", "upstream_id", "recharge_date"),
+    )