Empty collections return empty array

An endpoint that returns 404 when a collection is empty conflates two distinct states: "this endpoint does not exist" and "this collection has no items." Consumers must add special-case 404 handling to every list call, and any generic list component breaks for new users who have no data yet. Returning null instead of [] causes response.data.map is not a function in every consumer that did not add a null guard. iso-25010:2011 compatibility.interoperability requires a consistent response shape regardless of result count — consumers must be able to write one code path for all list responses.

Always return an empty array with 200 status and consistent pagination metadata when a collection has no items:

// Before -- inconsistent empty handling:
if (results.length === 0) {
  return Response.json({ message: 'No items found' }, { status: 404 })
}

// After -- consistent shape regardless of count:
return Response.json({
  data: results,  // [] when empty, same shape as non-empty
  meta: { page: 1, limit: 20, total: 0, totalPages: 0 }
})

This lets consumers write response.data.map(...) once and have it work whether the array has 0 or 1000 items. The rule is simple: 404 means the endpoint does not exist, never that the collection is empty.