feat(web): settings to keep the search open and hide home pickers; collapsible menu sections

- appearance settings get "collapse search" (off keeps the field always open)
  and separate switches for the activity and mood pickers on the home page;
  stored in ui_prefs (search_collapse, home_activities, home_moods)
- Collection and Admin headers in the sidebar fold their items; the state is
  remembered in the browser, a folded Admin shows the review queue badge;
  icon-only and phone layouts always show every item

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/i18n/locales/en/common.json

@@ -119,7 +119,10 @@
     "search_position": "Search position",
     "search_left": "Left",
     "search_center": "Center",
-    "search_right": "Right"
+    "search_right": "Right",
+    "search_collapse": "Collapse search",
+    "home_activities": "Activity picker on home",
+    "home_moods": "Mood picker on home"
   },
   "form": {
     "show_password": "Show password",