fix: drag onto file makes dragged item a child of that file

Dragging B onto A:
  ▶ File A
      File B

A becomes the parent, B becomes its child. No new group created.

src/views/waypoint-view.ts

@@ -1028,39 +1028,24 @@ export class WaypointView extends ItemView {
 		const dragged = removeById(this.plugin.waypointData.bookmarks);
 		if (!dragged) return;
 
-		// Find the target in its parent array
-		const findTarget = (items: BookmarkItem[]): { parent: BookmarkItem[]; idx: number } | null => {
-			const idx = items.findIndex(i => i.id === targetId);
-			if (idx >= 0) return { parent: items, idx };
-			for (const child of items) {
-				if (child.children) {
-					const result = findTarget(child.children);
-					if (result) return result;
+		// Find the target
+		const findTarget = (items: BookmarkItem[]): BookmarkItem | null => {
+			for (const item of items) {
+				if (item.id === targetId) return item;
+				if (item.children) {
+					const found = findTarget(item.children);
+					if (found) return found;
 				}
 			}
 			return null;
 		};
 
-		const targetInfo = findTarget(this.plugin.waypointData.bookmarks);
-		if (!targetInfo) return;
+		const target = findTarget(this.plugin.waypointData.bookmarks);
+		if (!target) return;
 
-		const target = targetInfo.parent[targetInfo.idx];
-		const newGroup: BookmarkItem = {
-			id: `bm-${Date.now()}-${Math.random().toString(36).slice(2, 6)}`,
-			type: 'group',
-			label: 'New Group',
-			filePath: '',
-			icon: '',
-			children: [
-				{ ...target, indent: target.indent + 1 },
-				{ ...dragged, indent: target.indent + 1 },
-			],
-			collapsed: false,
-			indent: target.indent,
-		};
-
-		// Replace target with the new group
-		targetInfo.parent.splice(targetInfo.idx, 1, newGroup);
+		// Make dragged item a child of the target
+		dragged.indent = target.indent + 1;
+		target.children.push(dragged);
 
 		this.plugin.saveWaypointData();
 		this.redraw();