feat: billing guest access

models/billing.py

@@ -0,0 +1,25 @@
+import datetime
+from typing import TYPE_CHECKING
+
+from sqlalchemy import ForeignKey
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from models import BaseModel
+if TYPE_CHECKING:
+    from models import Deal
+
+
+class DealBillRequest(BaseModel):
+    __tablename__ = 'deal_bill_requests'
+
+    deal_id: Mapped[int] = mapped_column(ForeignKey('deals.id'),
+                                         nullable=False,
+                                         primary_key=True,
+                                         unique=True)
+    deal: Mapped['Deal'] = relationship(back_populates='bill_request')
+
+    created_at: Mapped[datetime.datetime] = mapped_column(nullable=False)
+    paid: Mapped[bool] = mapped_column(nullable=False, default=False)
+
+    pdf_url: Mapped[str] = mapped_column(nullable=True)
+    invoice_number: Mapped[str] = mapped_column(nullable=True)