Servers like copyparty advertise search via a link to an OpenSearch
Description (OSD) document rather than embedding {searchTerms} directly
in the feed's <link rel="search"> href (the Calibre-Web style).
OpdsParser now stores the OSD URL when rel="search" and
type="application/opensearchdescription+xml" but the href lacks
{searchTerms}. OpdsBookBrowserActivity fetches that OSD document after
each feed load and parses the <Url template="..."> element with a
minimal inline expat parser to extract the actual search template.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
