feat(ui): cinematic movie and series details pages and dashboard hero (#1792)

.changes/dashboard-hero-cinematic-alignment.md

@@ -0,0 +1,6 @@
+---
+type: feature
+area: workspace
+---
+
+The dashboard hero now shares the details pages' look: the same light Continue button and chips, a series title without its "(Season 1)" marker, and the blurred poster alone as the backdrop when a title has none. The hero can be focused: ← and → switch slides, Enter follows the main action, and rotation pauses while the window is hidden.

.changes/portals-cinematic-vod-details.md

@@ -0,0 +1,7 @@
+---
+type: feature
+area: portals
+highlight: Cinematic movie and series pages
+---
+
+Movie and series pages open on a cinematic backdrop with chips, plot and one action row: a light Continue/Play button naming the next episode and the time left, a Trailer modal, and a "…" menu with other sources, external player, copy URL, reset progress and season actions. Cast & crew and Similar follow as rows. Without a 16:9 backdrop the hero shrinks to its content over the blurred poster.

.changes/portals-trailer-backdrop.md

@@ -0,0 +1,6 @@
+---
+type: feature
+area: portals
+---
+
+A new Playback setting, "Play trailers in details background" (off by default), plays a movie's or series' trailer muted behind the details a few seconds after the page opens, with a corner button to unmute. It stays off under reduced motion and on metered connections, and stops when the page scrolls away or the window loses focus.