Found by the HU-overlay E2E: PlexPlayer fetched qk.plexItem(id) WITHOUT lang,
so the in-player title/summary/rich detail stayed English even in HU mode while
the grid showed Hungarian (e.g. the player header read "127 Hours" over a grid
of "127 óra"). The S6 FE pass threaded lang through the grid, facets, info-page
and show queries but missed the player's own detail fetch. Now keyed by
plexLang() like the rest, so the player matches the active language.
FE gate: tsc / knip / lint clean; queryKeys tests pass. Verified live — the
player header now reads "127 óra" in HU mode.