fix(node): the node decides which files it will transcode, not the player

`BROWSER_INCOMPATIBLE_AUDIO_EXTS` named the two formats no browser decodes and
was read by nothing. The player asked for `.wma` and `.mpc` and no others, and
`music-player.js` called itself "kept in sync with the node's" constant — so the
entire restriction lived in the caller, and a member's own message is not the
caller.

What that let through: this converts a whole file and holds a transcode slot
shared with video streaming while it runs. One message naming a two-hour film
spends minutes of the operator's CPU and a slot every other viewer is queued
behind. `AUDIO_TRANSCODE_MAX_BYTES` catches the result, after the work is done;
only the extension catches the work.

The client comment now says what it is — an optimisation that saves asking for a
refusal — rather than implying it is the rule.

Two tests: a film is refused before ffmpeg is reached, and a WMA still passes,
because a gate that refuses everything is not a gate.

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

1 files changed, 6 insertions, 3 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/music-player.js b/packages/meshbay-hub/src/meshbay_hub/static/music-player.js
index 7c81f4e..5f2e33c 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/music-player.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/music-player.js
@@ -36,9 +36,12 @@ const MIME_BY_EXT = {
   wav: 'audio/wav', aac: 'audio/aac', m4a: 'audio/mp4',
 };
 
-// Kept in sync with the node's BROWSER_INCOMPATIBLE_AUDIO_EXTS
-// (webrtc_server.py) — both name the same two formats no mainstream
-// browser's <audio> element decodes natively.
+// The same two formats as the node's BROWSER_INCOMPATIBLE_AUDIO_EXTS
+// (webrtc_server.py), which is the one that decides: the node refuses a
+// transcode request for anything else. This is here so the player does not
+// ask for one it knows will be refused — not because it enforces the rule.
+// It used to be the only thing that did, and a member's own message never
+// passed through it.
 const NEEDS_TRANSCODE_RE = /\.(wma|mpc)$/i;
 
 function guessMime(name) {