`MediaServerClient.findByExternalIds` returned `MediaItem?`, so the Explore
"In these libraries" chooser could never show more than one copy per server.
A movie held by both a 4K library and an HD library on one Plex server
therefore resolved to whichever copy came back first, with no way to reach
the other.
Return every id-verified match instead. `/library/all` is already
server-wide and each `Metadata` entry carries its own `librarySectionID`,
so both copies come back labelled with no extra request; Plex was simply
taking `Metadata[0]` and the title ladder was returning on its first hit.
An exact-guid hit no longer short-circuits the title search either — a
library still on a legacy agent has a different primary guid and is
invisible to the `guid=` filter.
Copies are deduped by global key and ordered best-first, and each row now
states its resolution, since library names need not mention it.
Resolution passes merge rather than replace: the cross-server fan-out logs
and skips per-server failures, so a later pass can come back short a server
that answered an earlier one, and a failed pass no longer claims the title
left the library. Duplicate keys fold field by field, because Jellyfin's
library stamp is a best-effort ancestors lookup that returns the item bare
when it fails and an unstamped row is indistinguishable from its sibling.
Focus nodes are keyed by copy and reclaimed after a merge re-sorts the
rows, so a dpad user is not thrown to a different copy.
close#1754
edde746
bc0d14a749