feat: Add currency management feature with CRUD operations

- Introduced a new template for currency overview and management (`currencies.html`).
- Updated footer to include attribution to AllYouCanGET.
- Added "Currencies" link to the main navigation header.
- Implemented end-to-end tests for currency creation, update, and activation toggling.
- Created unit tests for currency API endpoints, including creation, updating, and activation toggling.
- Added a fixture to seed default currencies for testing.
- Enhanced database setup tests to ensure proper seeding and migration handling.

tests/e2e/conftest.py

@@ -64,6 +64,40 @@ def live_server() -> Generator[str, None, None]:
                 process.wait(timeout=5)
 
 
+@pytest.fixture(scope="session", autouse=True)
+def seed_default_currencies(live_server: str) -> None:
+    """Ensure a baseline set of currencies exists for UI flows."""
+
+    seeds = [
+        {"code": "EUR", "name": "Euro", "symbol": "EUR", "is_active": True},
+        {"code": "CLP", "name": "Chilean Peso", "symbol": "CLP$", "is_active": True},
+    ]
+
+    with httpx.Client(base_url=live_server, timeout=5.0) as client:
+        try:
+            response = client.get("/api/currencies/?include_inactive=true")
+            response.raise_for_status()
+            existing_codes = {
+                str(item.get("code"))
+                for item in response.json()
+                if isinstance(item, dict) and item.get("code")
+            }
+        except httpx.HTTPError as exc:  # noqa: BLE001
+            raise RuntimeError("Failed to read existing currencies") from exc
+
+        for payload in seeds:
+            if payload["code"] in existing_codes:
+                continue
+            try:
+                create_response = client.post("/api/currencies/", json=payload)
+            except httpx.HTTPError as exc:  # noqa: BLE001
+                raise RuntimeError("Failed to seed currencies") from exc
+
+            if create_response.status_code == 409:
+                continue
+            create_response.raise_for_status()
+
+
 @pytest.fixture(scope="session")
 def playwright_instance() -> Generator[Playwright, None, None]:
     """Provide a Playwright instance for the test session."""