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>

tests/test_routes/test_products.py

@@ -0,0 +1,94 @@
+"""Integration tests for product endpoints."""
+
+import uuid
+from datetime import date
+from decimal import Decimal
+
+import pytest
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
+
+from cartsnitch_api.models import NormalizedProduct, PriceHistory, Store
+
+
+@pytest.fixture
+async def product_data(db_engine, auth_headers):
+    """Seed products and price history."""
+    factory = async_sessionmaker(db_engine, class_=AsyncSession, expire_on_commit=False)
+    async with factory() as session:
+        store = Store(name="Meijer", slug="meijer")
+        product = NormalizedProduct(
+            canonical_name="Cheerios 18oz",
+            category="pantry",
+            brand="General Mills",
+            upc_variants=["016000275263"],
+        )
+        session.add_all([store, product])
+        await session.commit()
+        await session.refresh(store)
+        await session.refresh(product)
+
+        ph1 = PriceHistory(
+            normalized_product_id=product.id,
+            store_id=store.id,
+            observed_date=date(2026, 3, 1),
+            regular_price=Decimal("4.99"),
+            source="receipt",
+        )
+        ph2 = PriceHistory(
+            normalized_product_id=product.id,
+            store_id=store.id,
+            observed_date=date(2026, 3, 10),
+            regular_price=Decimal("5.49"),
+            source="receipt",
+        )
+        session.add_all([ph1, ph2])
+        await session.commit()
+
+        return {"product": product, "store": store, "headers": auth_headers}
+
+
+@pytest.mark.asyncio
+async def test_list_products(client, product_data):
+    resp = await client.get("/products", headers=product_data["headers"])
+    assert resp.status_code == 200
+    data = resp.json()
+    assert len(data) >= 1
+    assert data[0]["name"] == "Cheerios 18oz"
+
+
+@pytest.mark.asyncio
+async def test_search_products(client, product_data):
+    resp = await client.get("/products?q=Cheerios", headers=product_data["headers"])
+    assert resp.status_code == 200
+    assert len(resp.json()) == 1
+
+    resp = await client.get("/products?q=nonexistent", headers=product_data["headers"])
+    assert resp.status_code == 200
+    assert len(resp.json()) == 0
+
+
+@pytest.mark.asyncio
+async def test_get_product_detail(client, product_data):
+    pid = str(product_data["product"].id)
+    resp = await client.get(f"/products/{pid}", headers=product_data["headers"])
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["name"] == "Cheerios 18oz"
+    assert data["brand"] == "General Mills"
+    assert len(data["prices_by_store"]) >= 1
+
+
+@pytest.mark.asyncio
+async def test_get_product_not_found(client, auth_headers):
+    resp = await client.get(f"/products/{uuid.uuid4()}", headers=auth_headers)
+    assert resp.status_code == 404
+
+
+@pytest.mark.asyncio
+async def test_get_product_prices(client, product_data):
+    pid = str(product_data["product"].id)
+    resp = await client.get(f"/products/{pid}/prices", headers=product_data["headers"])
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["product_name"] == "Cheerios 18oz"
+    assert len(data["data_points"]) == 2