iPhone: full client timeline + self-diagnosing watchdog

Every step now beacons with millisecond offsets:
branch-decision -> new-hls-ok -> loadsource-called -> attach-ok ->
manifest-loaded -> level-loaded -> frag-loaded(1..2) -> buffer-appended
-> do-play -> play-resolved/play-rejected(name) + EVERY hls.js error
(fatal and silent retries). Plus a watchdog: if not playing within 15s,
it snapshots {readyState, networkState, paused, buffered, hls.state,
overlay text} every 15s (x6) — so a silent death anywhere produces a
state dump instead of nothing.

Verified on desktop: healthy timeline lands end-to-end, playback OK,
18/18 tests. assets v=13.

static/index.html

@@ -6,7 +6,7 @@
 <title>ani-web</title>
 <link rel="icon" href="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 64 64'%3E%3Crect width='64' height='64' rx='14' fill='%23f97316'/%3E%3Ctext x='32' y='45' font-family='sans-serif' font-size='42' font-weight='700' text-anchor='middle' fill='%230e0f13'%3Ea%3C/text%3E%3C/svg%3E">
 
-<link rel="stylesheet" href="style.css?v=12">
+<link rel="stylesheet" href="style.css?v=13">
 </head>
 <body>
 <header>
@@ -30,6 +30,6 @@
      max-age=300 in browser AND possibly in your HTTPS proxy, and a stale
      copy is exactly how users keep seeing an old UI after a deploy -->
 <script src="hls.min.js"></script>
-<script src="app.js?v=12"></script>
+<script src="app.js?v=13"></script>
 </body>
 </html>