playlists: refuse a body no frame can carry, and say which one

A DataChannel send() throws above the max-message-size the node advertises
(aiortc: 65536), so the 1 MB body cap was unreachable and each body push
swallowed the difference in a bare catch. Cap at 62 KB after sealing, name
the playlist in the sync result, keep syncing the rest.

Measured: 1000 tracks seal to 53 276 bytes, so the ceiling is ~1200.

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

1 files changed, 12 insertions, 5 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/playlist-menu.js b/packages/meshbay-hub/src/meshbay_hub/static/playlist-menu.js
index e2fb3f9..70c105d 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/playlist-menu.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/playlist-menu.js
@@ -197,11 +197,18 @@ function PlaylistMenuButton({ userId, lists, reload, onPlayQueue, onSync, cached
           // playlist subkey existed — and an AES handle is non-extractable, so
           // there is nothing to derive it from. One sign-in with the passphrase
           // fixes it for good; a code on screen does not say that.
-          say(r && r.ok
-            ? `${t('playlists.synced')} (${r.pushed || 0}↑ ${r.pulled || 0}↓)`
-            : (why === 'no_key'
-              ? t('playlists.err_no_key')
-              : `${t('playlists.sync_failed')}: ${why}`));
+          // A playlist too large to send is reported ahead of the totals. The
+          // sync itself worked — everything else moved — so `ok` is true, and
+          // saying "synced" while one playlist silently stayed behind would be
+          // the lie this whole report exists to stop.
+          const big = (r && r.tooLarge) || [];
+          say(big.length
+            ? t('playlists.err_too_large', { name: big[0], n: 1000 })
+            : (r && r.ok
+              ? `${t('playlists.synced')} (${r.pushed || 0}↑ ${r.pulled || 0}↓)`
+              : (why === 'no_key'
+                ? t('playlists.err_no_key')
+                : `${t('playlists.sync_failed')}: ${why}`)));
         },
       },
     ]);