fix(ui): E31 S2 — the tab names the object, the channel header wraps, the player fits a short window

- The browser tab names the place and the object: PageHeading reports the
  view's own title (lib/documentTitle), so a channel, playlist or any Plex
  view reads "<object> · <module> · Siftlode" however it was opened; the
  Feed is named too; a season adds its show (tabTitle).
- The channel page's tab + action row wraps and lets the tag lane fold into
  "+N": at 1024 it ran past the edge and the page scrolled sideways.
- The YouTube player card's width is capped from the window height less the
  chrome measured under the video: at 133% zoom (685px) it cut its channel row.
- Plex certificate words (Not Rated, Approved, Passed) are named through the
  vocabulary on the info badge, show page, collection, filter and chips.
- DESIGN.md: the zoom target is 125% and 133%, not 200% (decision log).

frontend/src/components/Playlists.tsx

@@ -63,6 +63,7 @@ import { CheckRow } from "./ui/NativeControls";
 import { useReturnFocus } from "./ui/useReturnFocus";
 import { MoreButton } from "./ui/MoreButton";
 import { HiddenFilterCue } from "./ui/HiddenFilterCue";
+import { PageHeading } from "./ui/Headings";
 import { useCopyItems } from "./copyItems";
 
 // The playlist detail is a HYBRID table (E4 S4): real sortable/filterable column headers over a
@@ -875,7 +876,9 @@ export default function Playlists() {
                       aria-label={t("playlists.rename")}
                     />
                   ) : (
-                    <h2 className="text-lg font-semibold truncate">{plName(detail)}</h2>
+                    <PageHeading className="text-lg font-semibold truncate">
+                      {plName(detail)}
+                    </PageHeading>
                   )}
                   <div className="ml-auto flex gap-1.5 items-center shrink-0">
                     {linked && detail.dirty && (