feat: merge cartsnitch/api into api/ subdirectory

Consolidate API gateway service into monorepo.
Squashed from https://github.com/cartsnitch/api main (89bacb1).

Co-Authored-By: Paperclip <noreply@paperclip.ing>

src/cartsnitch_api/models/coupon.py

@@ -0,0 +1,42 @@
+"""Coupon model."""
+
+import uuid
+from datetime import date, datetime
+from decimal import Decimal
+from typing import TYPE_CHECKING
+
+from sqlalchemy import Boolean, Date, DateTime, ForeignKey, Numeric, String
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from cartsnitch_api.constants import DiscountType
+from cartsnitch_api.models.base import Base, TimestampMixin, UUIDPrimaryKeyMixin
+
+if TYPE_CHECKING:
+    from cartsnitch_api.models.product import NormalizedProduct
+    from cartsnitch_api.models.store import Store
+
+
+class Coupon(UUIDPrimaryKeyMixin, TimestampMixin, Base):
+    """A coupon or deal for a product at a store."""
+
+    __tablename__ = "coupons"
+
+    store_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("stores.id"), nullable=False)
+    normalized_product_id: Mapped[uuid.UUID | None] = mapped_column(
+        ForeignKey("normalized_products.id")
+    )
+    title: Mapped[str] = mapped_column(String(300), nullable=False)
+    description: Mapped[str | None] = mapped_column(String(1000))
+    discount_type: Mapped[DiscountType] = mapped_column(String(20), nullable=False)
+    discount_value: Mapped[Decimal | None] = mapped_column(Numeric(10, 2))
+    min_purchase: Mapped[Decimal | None] = mapped_column(Numeric(10, 2))
+    valid_from: Mapped[date | None] = mapped_column(Date)
+    valid_to: Mapped[date | None] = mapped_column(Date)
+    requires_clip: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+    coupon_code: Mapped[str | None] = mapped_column(String(100))
+    source_url: Mapped[str | None] = mapped_column(String(500))
+    scraped_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
+
+    # Relationships
+    store: Mapped["Store"] = relationship(back_populates="coupons")
+    normalized_product: Mapped["NormalizedProduct | None"] = relationship(back_populates="coupons")