API Endpoint and Serializer Authoring (apps/api)

A. Adding a Resource or Action Endpoint

1. Classify the endpoint type

• Resource endpoint (GET /v1/sites/{id}/cameras): implies the resource exists; return HTTP 409 when the required product is absent.
• Action endpoint: advisory; always return HTTP 200 with a capability_not_available envelope when the capability is missing — never 404 or 409 for action endpoints.

2. Wire cursor-based pagination

Use Cursor and paginate() from apps/api/src/unifi_api/services/pagination.py:

from unifi_api.services.pagination import Cursor, InvalidCursor, paginate