UAT: 14/15 passed. Bug fixed: folders/rootFolders array alias in fetchFolders caused
duplicate folder row on creation (rootFolders = [...list] breaks the shared reference).
Sidebar: Folders section now has a collapse/expand chevron, collapsed by default.
State: Phase 4 complete, Phase 5 (Cloud Storage Backends) is next.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
curo1305