feat(workspace): hashtag page shows the live outliner of each note's tagged branches, edited in place

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

frontend/src/features/workspace/OutlinerTree.tsx

@@ -42,6 +42,8 @@ export interface OutlinerTreeProps {
   /** Deleting a selection over several bullets in one step: the first bullet with its new text, the
    *  bullets to delete, and children of the last bullet that move under the first */
   onReplaceRange?: (first: DocumentBlock, deleteIds: string[], movedChildren: DocumentBlock[]) => void;
+  /** The empty area below the last bullet (click adds one); off where several trees stack (hashtag page) */
+  trailingArea?: boolean;
 }
 
 export const OutlinerTree = forwardRef<OutlinerTreeHandle, OutlinerTreeProps>(({
@@ -71,6 +73,7 @@ export const OutlinerTree = forwardRef<OutlinerTreeHandle, OutlinerTreeProps>(({
   onUndo,
   onRedo,
   onReplaceRange,
+  trailingArea = true,
 }, ref) => {
   const [focusedBlockId, setFocusedBlockId] = useState<string | null>(null);
 
@@ -955,7 +958,7 @@ export const OutlinerTree = forwardRef<OutlinerTreeHandle, OutlinerTreeProps>(({
         );
       })}
 
-      {canEdit && (
+      {canEdit && trailingArea && (
         <div
           className={`${compact ? 'min-h-[2.5rem]' : 'min-h-[14rem]'} pt-2 pl-2 transition-colors cursor-text ${
             dragOverIndex === blocks.length ? 'border-t-2 border-accent bg-accent/10 rounded' : ''