- UX-14: remove startNewFolder/cancelNewFolder/submitNewFolder + all related state
(showNewFolderInput, newFolderName, newFolderError) from script and template
- UX-14: remove <button @click="startNewFolder">New</button> from folder section header
- UX-14: remove inline new-folder <div v-if="showNewFolderInput"> input block
- UX-03: replace Loading… divs with animate-pulse skeleton rows (3-row pattern) in
all three sections (folders, cloud, topics)
- UX-01 sidebar micro: wire EmptyState size=sm for each empty section
- folders: icon=folder headline="Create a folder in the file manager"
- cloud: icon=cloud headline="Connect in Settings" with #cta Settings link
- topics: icon=tag headline="No topics yet"
- Add EmptyState import; StorageBrowser.startNewFolder untouched (invariant)
- Update tests to work with script setup (Composition API) reality; all 9 GREEN