feat(plex): sort direction, genre any/all, multi-person filters; fix back-nav + player stop

UAT follow-ups on the Plex filter epic:
- Sort now has an asc/desc toggle (sort_dir), applied to any sort field.
- Genre multi-select gains an Any/All mode (genre_mode: OR vs AND containment).
- Director/actor/studio become multi-value: people AND (titles featuring all selected),
  studios OR; clicking them on the info page stacks (unions) instead of replacing, and
  the sidebar shows each as a removable 'Active' chip.
- fix(history): clicking a metadata filter on the info page now pushes a fresh grid
  entry instead of history.back(), so browser Back returns to the info page rather than
  leaving the Plex module.
- fix(player): fully tear down the <video> + hls on unmount and guard late play() calls,
  so backing out of a just-started video no longer leaves audio playing in the background.
i18n en/hu/de (match any/all, sort direction).

frontend/src/components/PlexInfo.tsx

@@ -181,7 +181,7 @@ export default function PlexInfo({ detail, variant, onPlay, onClose, onStateChan
               {detail.studio && (
                 <Filterable
                   className={mutedCls}
-                  onClick={onFilter ? () => onFilter({ studio: detail.studio! }) : undefined}
+                  onClick={onFilter ? () => onFilter({ studios: [detail.studio!] }) : undefined}
                 >
                   {detail.studio}
                 </Filterable>
@@ -232,7 +232,7 @@ export default function PlexInfo({ detail, variant, onPlay, onClose, onStateChan
                   <span key={d}>
                     <Filterable
                       className="font-medium"
-                      onClick={onFilter ? () => onFilter({ director: d }) : undefined}
+                      onClick={onFilter ? () => onFilter({ directors: [d] }) : undefined}
                     >
                       {d}
                     </Filterable>
@@ -331,7 +331,7 @@ export default function PlexInfo({ detail, variant, onPlay, onClose, onStateChan
                 return onFilter ? (
                   <button
                     key={i}
-                    onClick={() => onFilter({ actor: c.name })}
+                    onClick={() => onFilter({ actors: [c.name] })}
                     title={t("plex.info.filterActor", { name: c.name })}
                     className="group/cast w-20 shrink-0 text-center"
                   >