web: trim the library to one toolbar and a folder menu

Fold the hint, ADD FOLDER and the two view switches onto a single row,
with the switches drawn as icons, and move a folder's rescan and remove
onto a right click — they belong to the folder, so they are asked for
rather than always on screen.

docker/frontend/src/i18n/en.ts

@@ -234,6 +234,7 @@ export const en: Dict = {
   'lib.remove': 'REMOVE',
   'lib.reconnect': 'GRANT ACCESS AGAIN',
   'lib.tree': 'FOLDERS',
+  'lib.nodeHint': 'Right-click (or Shift+F10) to rescan or remove the folder.',
   'lib.viewPreview': 'SINGLE',
   'lib.viewGrid': 'ALL THUMBS',
   'lib.open': 'Open in the studio',