web: force hls.js archive playback on chromium

apps/web/app.js

@@ -219,6 +219,17 @@ async function ensureHlsPlayerCtor() {
   return hlsModulePromise;
 }
 
+function shouldUseNativeHls(video) {
+  const ua = navigator.userAgent || "";
+  const vendor = navigator.vendor || "";
+  const isIos = /iPhone|iPad|iPod/i.test(ua);
+  const isSafari =
+    /Safari/i.test(ua) &&
+    /Apple/i.test(vendor) &&
+    !/CriOS|FxiOS|EdgiOS|OPiOS|Chrome|Chromium/i.test(ua);
+  return (isIos || isSafari) && Boolean(video.canPlayType("application/vnd.apple.mpegurl"));
+}
+
 async function mountArchivePlayer(name) {
   clearPlayerSignals();
   destroyArchivePlayer();
@@ -241,7 +252,7 @@ async function mountArchivePlayer(name) {
   mount.appendChild(video);
 
   const archiveUrl = `/api/archive/${encodeURIComponent(name)}/master.m3u8`;
-  if (video.canPlayType("application/vnd.apple.mpegurl")) {
+  if (shouldUseNativeHls(video)) {
     video.src = archiveUrl;
     void video.play().catch(() => {});
     return;

evolution/proposals/ECP-0074-archive-hls-engine-selection.md

@@ -0,0 +1,21 @@
+# ECP-0074: Archive HLS Engine Selection For Chromium
+
+## Context
+
+Archive mode currently chooses native HLS whenever `video.canPlayType("application/vnd.apple.mpegurl")` is non-empty.
+
+Chromium may report support but still fail to actually play event-style fMP4 HLS in this path, leaving the player stuck at `readyState = 0`.
+
+## Decision
+
+Use native HLS only on Safari/iOS user agents. For all other browsers (including Chromium), force `hls.js` playback.
+
+## Why
+
+- Restores archive playback on Chrome/Chromium.
+- Keeps Safari native path where it is reliable.
+- Preserves a single URL and UI flow (`/api/archive/.../master.m3u8`).
+
+## Reversibility
+
+Revert the UA gate and return to the previous `canPlayType`-only check.