music: play, play next, add to queue

The player's queue could only be replaced: every onPlayQueue reset
tracks/order/pos together. It becomes one reducer (queue-ops.js) with
an `op`, because two appends batched into one tick cannot both read the
track count out of separate useStates.

A shared pop-up menu (menu.js) carries the three verbs, on right-click
and on a dots button. A track row is now a div holding two buttons: a
button cannot contain a button.

Found by the browser probe: both music wrappers took two arguments and
forwarded two, so every "add to queue" arrived as a plain play.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/group-page.js b/packages/meshbay-hub/src/meshbay_hub/static/group-page.js
index 4de33b9..060fd6e 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/group-page.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/group-page.js
@@ -173,11 +173,18 @@ function GroupPage({ groupId, group, token, username, userId, userPrefs,
   const [searchListed, setSearchListed] = useState(true);
   // MusicBrainz on/off (per-group) — docs/musicbay.md §3.2.
   const [musicbrainzConfig, setMusicbrainzConfig] = useState(null);
-  const onPlayQueue = useCallback((tracks, startIndex) => {
-    setVideoEntry(null);
+  // `op` rides through to the shell — 'replace', 'next' or 'append'
+  // (docs/playlists.md §9.2). It has to be named here: a wrapper that takes
+  // two arguments and forwards two silently turns every "add to queue" in this
+  // group into a "play", and nothing about that reads as wrong at the call
+  // site or here.
+  const onPlayQueue = useCallback((tracks, startIndex, op) => {
+    // Only a replace changes what is on screen; enqueueing something does not
+    // close whatever the reader was already looking at.
+    if (!op || op === 'replace') setVideoEntry(null);
     if (parentOnPlayQueue) {
       const annotated = tracks.map(tr => tr.groupId ? tr : { ...tr, groupId });
-      parentOnPlayQueue(annotated, startIndex, { transportRef, gekRef, groupId });
+      parentOnPlayQueue(annotated, startIndex, { transportRef, gekRef, groupId }, op);
     }
   }, [parentOnPlayQueue, groupId]);
   // Paired ≠ operator account. `is_node_admin` says the hub account owning this