fix(mobile): sheets above the keyboard, emoji picker, cleaner header

- FormSheet: create dialogs (task list, shopping list, folder) as bottom
  sheet right above the on-screen keyboard (visualViewport), large fields;
  centred or anchored dialog on desktop
- Emoji picker: category icons keep their sprite size (no doubled icons,
  round highlight), one 'Zuletzt verwendet' (library category, German
  names), sheet and picker height follow the keyboard
- Mobile header no longer repeats the current section next to the logo

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

frontend/src/features/workspace/WorkspaceView.tsx

@@ -49,6 +49,7 @@ import {
   RealtimeTransport,
 } from '../../lib/api';
 import { UnifiedShareModal } from '../../components/UnifiedShareModal';
+import { FormSheet } from '../../components/FormSheet';
 import { sendDocOps } from '../../lib/docSync/oneoff';
 import { useMobileActions } from '../../context/MobileActionContext';
 import { DocumentEditor, DocSaveStatus } from './DocumentEditor';
@@ -340,7 +341,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
     if (e) {
       setNewFolderCoords({
         x: Math.min(e.clientX, window.innerWidth - 270),
-        y: Math.min(e.clientY, window.innerHeight - 130),
+        y: Math.min(e.clientY, window.innerHeight - 200),
       });
     } else {
       setNewFolderCoords({ x: 100, y: 150 });
@@ -2196,55 +2197,22 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
 
       {/* New Folder Popover (small & positioned near click, asks only for name & OK) */}
       {showNewFolderModal && (
-        <div
-          className="fixed inset-0 z-50 bg-black/20"
-          onClick={() => setShowNewFolderModal(false)}
+        <FormSheet
+          title={newFolderParentPath ? `Unterordner in "${newFolderParentPath}"` : 'Neuer Ordner'}
+          icon={<FolderPlus className="w-4 h-4 text-accent" />}
+          onClose={() => setShowNewFolderModal(false)}
+          onSubmit={handleCreateFolderSubmit}
+          anchor={newFolderCoords}
         >
-          <form
-            onSubmit={handleCreateFolderSubmit}
-            onClick={(e) => e.stopPropagation()}
-            style={
-              newFolderCoords
-                ? { top: `${newFolderCoords.y}px`, left: `${newFolderCoords.x}px` }
-                : undefined
-            }
-            className="fixed w-64 bg-panel border border-border rounded-card p-3 shadow-lg space-y-2.5 z-50 text-xs"
-          >
-            <div className="font-semibold text-main text-xs flex items-center justify-between">
-              <span className="truncate">{newFolderParentPath ? `Unterordner in "${newFolderParentPath}"` : 'Neuer Ordner'}</span>
-              <button
-                type="button"
-                onClick={() => setShowNewFolderModal(false)}
-                className="text-faint hover:text-main cursor-pointer"
-              >
-                <X className="w-3.5 h-3.5" />
-              </button>
-            </div>
-            <input
-              type="text"
-              autoFocus
-              value={newFolderName}
-              onChange={(e) => setNewFolderName(e.target.value)}
-              placeholder="Ordnername"
-              className="input-field w-full px-2 py-1 text-xs"
-            />
-            <div className="flex justify-end gap-1.5 pt-1">
-              <button
-                type="button"
-                onClick={() => setShowNewFolderModal(false)}
-                className="btn-action px-2.5 py-1 text-xs"
-              >
-                Abbrechen
-              </button>
-              <button
-                type="submit"
-                className="btn-primary px-3 py-1 text-xs font-semibold"
-              >
-                OK
-              </button>
-            </div>
-          </form>
-        </div>
+          <input
+            type="text"
+            autoFocus
+            value={newFolderName}
+            onChange={(e) => setNewFolderName(e.target.value)}
+            placeholder="Ordnername"
+            className="input-field w-full h-11 sm:h-8 px-2.5 text-base sm:text-xs"
+          />
+        </FormSheet>
       )}
 
       {/* Unified Sharing Modal (Strictly Read-Only for Docs and Folders) */}