Playback page: show 'E{n} — episode title' line under the video

The name was only in the grid tooltip (hover-only, invisible on touch).
Add a persistent now-playing line between the player and controls:
'E1 — Ryomen Sukuna'. setNowEp() runs on every play() and refreshes
when the async Jikan name lands late. Bumped asset version to v=3.

static/style.css

@@ -163,6 +163,8 @@ button.tiny.on { border-color: var(--acc); color: var(--acc); }
 .del:hover { border-color: #f87171; color: #f87171; }
 
 .eps { display: grid; grid-template-columns: repeat(auto-fill, minmax(64px, 1fr)); gap: 0.4rem; }
+.now-ep { font-size: .95rem; color: var(--muted); margin: .1rem 0 .45rem; }
+
 .ep { position: relative; font-size: 0.9rem; }
 .ep.filler { opacity: 0.55; }
 .ep.done { opacity: 0.5; }