feat(ui): expandable season description and episode info dialog

Season descriptions get the same show more/less toggle as the hero
(new shared ExpandableTextComponent); episode cards and list rows get
an info button that opens a dialog with the full plot, duration, air
date and a Play action — card heights stay fixed and click-to-play
semantics stay intact. Also: drop the per-frame backdrop blur on the
player card and make the watch-enter scroll instant so the hero morph
stops competing for frame budget.

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

libs/ui/playback/src/lib/portal-inline-player/portal-inline-player.component.scss

@@ -16,7 +16,8 @@
     box-shadow:
         0 20px 56px rgba(25, 20, 20, 0.12),
         inset 0 1px 0 rgba(255, 255, 255, 0.8);
-    backdrop-filter: blur(18px);
+    // No backdrop-filter here: blurring over a live video viewport forces an
+    // expensive re-blur every frame and makes the browse↔watch morph stutter.
 }
 
 .player-shell__header {