Playback: retry flaky upstream, faster proxy fail, cache /stream in browser

- upstream._get: one 300ms retry on transient errors (CF 403/503, 429,
  5xx); 404 stays final. Fixes the 502 cluster that hls.js couldn't
  recover from (fragLoadTimeOut x3 in error log)
- /stream: upstream timeout 12s < hls.js fragLoadingTimeOut (20s), so a
  hung segment 502s first and hls.js retries instead of fatal-timing-out
- /stream responses: Cache-Control public max-age=86400 (VOD + token is
  the exact upstream URL => immutable); re-opens/re-seeks skip the proxy
- /api/stream: drop unused qualities (frontend never read it; saved a
  ~0.2s cold upstream round-trip per episode)
- app.js/style.css: max-age=300 instead of no-store
- test_history_page_and_delete: stale selector (home redesign removed
  the 'view all' link; use 'history ->')

server/upstream.py

@@ -48,11 +48,19 @@ _ANIME_LINK = re.compile(r'anime/([a-z0-9-]+)-(\d+)"[^>]*title="([^"]*)"')
 
 
 def _get(url, **kw):
-    r = _session().get(url, **H, **kw)
-    if r.status_code in (403, 503) or "Just a moment" in r.text[:500]:
-        raise RuntimeError(f"blocked by cloudflare: {url}")
-    r.raise_for_status()
-    return r
+    # ponytail: one retry (300ms) on transient upstream errors (Cloudflare
+    # 403/503, 429, 5xx); 404 and other 4xx are final. Failing fast matters:
+    # hls.js's fragLoadingTimeOut (20s) races curl's timeout (20s), so a
+    # quick 502 lets hls.js's own frag retries (6x, backoff) do the waiting
+    for attempt in range(2):
+        r = _session().get(url, **{**H, **kw})  # kw overrides H (e.g. timeout)
+        if not (r.status_code in (403, 429, 503) or r.status_code >= 500
+                or "Just a moment" in r.text[:500]):
+            r.raise_for_status()
+            return r
+        if attempt:
+            raise RuntimeError(f"upstream {r.status_code}: {url}")
+        time.sleep(0.3)
 
 
 def _search(q):
@@ -122,19 +130,12 @@ def _master_m3u8(ep_id, lang="eng"):
     return None
 
 
-def _master_variants(master_url):
-    """Step 7: parse #EXT-X-STREAM-INF lines -> ['1920x1080', ...] (for display)"""
-    text = _get(master_url).text
-    return re.findall(r"RESOLUTION=(\d+x\d+)", text)
-
-
 # cached public API (TTLs in seconds)
 search = lambda q: _cached(f"search:{q.lower()}", 300, _search, q)
 details = lambda s: _cached(f"details:{s}", 3600, _details, s)
 episodes = lambda i: _cached(f"episodes:{i}", 300, _episodes, i)  # 5m: airing shows gain eps
 languages = lambda e: _cached(f"languages:{e}", 3600, _languages, e)
 master_m3u8 = lambda e, l="eng": _cached(f"master:{e}:{l}", 3600, _master_m3u8, e, l)
-master_variants = lambda u: _cached(f"variants:{u}", 3600, _master_variants, u)
 
 
 if __name__ == "__main__":