jellyfin panel app: browse, detail and player

adds the /jellyfin screen and its two panels (nav + view) on top of the
jellyfin sidecar, following the photos/invoiceshelf shape.

the transcode path is a progressive mp4 rather than hls, so no hls.js
dependency is added under the frozen-install rule. that stream has no
length and no byte ranges, so the player owns its own scrubber and seeks
by re-negotiating at a new startTimeTicks, tracking offset + currentTime;
a direct file keeps native controls. the hls url is still returned, so
switching later is a player change only.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/apps/officer-web/App.tsx

@@ -48,6 +48,8 @@ export function App() {
             <Route path="/headscale/:section" element={<Dashboard.HeadscaleScreen />} />
             <Route path="/photos" element={<Dashboard.PhotosScreen />} />
             <Route path="/photos/:section" element={<Dashboard.PhotosScreen />} />
+            <Route path="/jellyfin" element={<Dashboard.JellyfinScreen />} />
+            <Route path="/jellyfin/:section" element={<Dashboard.JellyfinScreen />} />
             <Route path="/transmission" element={<Dashboard.TransmissionScreen />} />
             <Route path="/transmission/:section" element={<Dashboard.TransmissionScreen />} />
             <Route path="/invoices" element={<Dashboard.InvoicesScreen />} />