Update the OPDS section of the API reference to reflect the now-working
catalog:
- Document the page/per_page parameters and that paging is driven by the
rel=next/previous/first/last links plus OpenSearch paging metadata.
- Refresh the example feed XML to show the pagination links, opensearch
namespace/elements, and standard Atom <title>/<author> elements.
- Document the search endpoint's two modes: OpenSearch description
(application/opensearchdescription+xml, no q) and results feed (with q),
with an example description document.