ui: no-store cache headers, synopsis below episode grid

- no-store on everything except /stream: stale cached app.js (old CDN
  hls.js ref) was the cause of the black screen — video plays fine in a
  real Chromium once the fresh JS loads (verified via playwright)
- synopsis moved under the episode grid

app.py

@@ -33,6 +33,15 @@ def _upstream(fn, *a, **kw):
         raise HTTPException(502, f"upstream error: {e}")
 
 
+@app.middleware("http")
+async def no_cache(request, call_next):
+    # ponytail: no-store on everything except /stream (segments should cache)
+    r = await call_next(request)
+    if not request.url.path.startswith("/stream"):
+        r.headers["Cache-Control"] = "no-store"
+    return r
+
+
 @app.get("/api/search")
 def api_search(q: str = Query(min_length=1)):
     return _upstream(upstream.search, q)