reconcileRemoteLayers() could wipe all local tabs when Automerge sync
or BroadcastChannel delivered empty layer data (CRDT initial state,
sync race). This caused clicking tabs to show an infinite-loading
dashboard. Now: empty remote layers are rejected when an active module
exists, and the current module always stays in the tab list.
Also adds 10s fetch timeout to TabCache.fetchAndInject() to prevent
infinite loading spinners on slow/failed module fetches.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Jeff Emmett
433833da0c