Add Checkbox ETTN receipts for Nova Poshta COD waybills

Cashier creates an ETTN receipt in Checkbox bound to the TTN with payment
control; Checkbox fiscalizes it itself when the parcel is paid for.

- cash_registers (Fernet-encrypted license key / PIN) and receipts tables
- Checkbox HTTP client + stub (ETTN does not work on test registers)
- two-phase create via ARQ job, timeout reconciliation, cron status polling
- /receipts and /cash-registers API, audit records
- dashboard: per-order and bulk create, prepayment, cancel; cash registers page

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

backend/tests/test_receipts_router.py

@@ -0,0 +1,78 @@
+"""Тесты роутера чеков: роли, постановка задач после commit, ответ с ошибками по заказам."""
+
+from __future__ import annotations
+
+import uuid
+from datetime import UTC, datetime
+from typing import Any
+
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.api.deps import get_current_user
+from app.db.models.receipt import Receipt, ReceiptStatus
+from app.db.models.user import User, UserRole
+from app.main import app
+from app.services import receipts as receipts_service
+from app.services.task_queue import get_task_queue
+
+
+class FakeQueue:
+    def __init__(self) -> None:
+        self.jobs: list[tuple[str, tuple[Any, ...]]] = []
+
+    async def enqueue(self, function: str, *args: Any) -> None:
+        self.jobs.append((function, args))
+
+
+def _user(role: UserRole) -> User:
+    return User(id=uuid.uuid4(), email="t@e.ua", password_hash="x", full_name="Т", role=role)
+
+
+@pytest.fixture
+def queue(monkeypatch: pytest.MonkeyPatch) -> FakeQueue:
+    fake = FakeQueue()
+    receipt = Receipt(
+        id=uuid.uuid4(),
+        order_id="1",
+        waybill_number="20450123456789",
+        total_kopecks=120000,
+        prepayment_kopecks=0,
+        cod_kopecks=120000,
+        status=ReceiptStatus.PENDING,
+        created_at=datetime.now(UTC),
+    )
+
+    async def fake_request(session: Any, items: Any, *, user: Any, request: Any) -> Any:
+        return receipts_service.RequestResult(created=[receipt], errors={"2": "У заказа нет ТТН"})
+
+    async def fake_commit(self: AsyncSession) -> None:
+        return None
+
+    monkeypatch.setattr(receipts_service, "request_receipts", fake_request)
+    monkeypatch.setattr(AsyncSession, "commit", fake_commit)
+    app.dependency_overrides[get_task_queue] = lambda: fake
+    yield fake
+    app.dependency_overrides.clear()
+
+
+def test_viewer_cannot_create(queue: FakeQueue) -> None:
+    app.dependency_overrides[get_current_user] = lambda: _user(UserRole.VIEWER)
+    response = TestClient(app).post("/api/v1/receipts", json={"items": [{"order_id": "1"}]})
+    assert response.status_code == 403
+    assert queue.jobs == []
+
+
+def test_cashier_creates_and_enqueues(queue: FakeQueue) -> None:
+    app.dependency_overrides[get_current_user] = lambda: _user(UserRole.CASHIER)
+
+    response = TestClient(app).post(
+        "/api/v1/receipts", json={"items": [{"order_id": "1"}, {"order_id": "2"}]}
+    )
+
+    assert response.status_code == 202
+    body = response.json()
+    assert [r["order_id"] for r in body["created"]] == ["1"]
+    assert body["errors"] == {"2": "У заказа нет ТТН"}
+    assert queue.jobs == [("create_ettn_receipt", (body["created"][0]["id"],))]