feat: drag onto file bookmark creates parent note + fix calendar layout

Drag-and-drop:
- Dropping a bookmark onto a file bookmark (middle zone) creates a new
  parent note group containing both items
- Dropping onto a group still moves into the group as before
- All file/group bookmarks now accept drops (3-zone behavior)

Calendar:
- Fixed broken table layout caused by display:flex on td elements
- Uses vertical-align:middle instead for cell content centering
- Calendar cells still have configurable height via CSS variable

src/views/waypoint-view.ts

@@ -604,7 +604,7 @@ export class WaypointView extends ItemView {
 				rowEl.addClass('waypoint-bm-dragging');
 			});
 
-			const canAcceptChildren = isGroup || (item.children && item.children.length > 0);
+			const canAcceptChildren = true; // all file/group bookmarks can accept drops
 
 			rowEl.addEventListener('dragend', () => {
 				this.dragId = null;
@@ -646,7 +646,11 @@ export class WaypointView extends ItemView {
 
 				const dropInto = (rowEl as any).__dropInto;
 				if (dropInto && canAcceptChildren) {
+					if (isGroup) {
 						this.moveBookmarkToGroup(draggedId, item.id);
+					} else {
+						this.createParentNoteAndMove(draggedId, item.id);
+					}
 				} else {
 					const dropAbove = (rowEl as any).__dropAbove;
 					this.moveBookmarkToPosition(draggedId, item.id, dropAbove);
@@ -1001,6 +1005,64 @@ export class WaypointView extends ItemView {
 		this.redraw();
 	}
 
+	/**
+	 * Create a new parent note group at the target's position,
+	 * containing both the target and the dragged item.
+	 */
+	private createParentNoteAndMove(draggedId: string, targetId: string): void {
+		const removeById = (items: BookmarkItem[]): BookmarkItem | null => {
+			const idx = items.findIndex(i => i.id === draggedId);
+			if (idx >= 0) {
+				const [removed] = items.splice(idx, 1);
+				return removed;
+			}
+			for (const child of items) {
+				if (child.children) {
+					const found = removeById(child.children);
+					if (found) return found;
+				}
+			}
+			return null;
+		};
+
+		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;
+				}
+			}
+			return null;
+		};
+
+		const targetInfo = findTarget(this.plugin.waypointData.bookmarks);
+		if (!targetInfo) return;
+
+		const target = targetInfo.parent[targetInfo.idx];
+		const newGroup: BookmarkItem = {
+			id: `bm-${Date.now()}-${Math.random().toString(36).slice(2, 6)}`,
+			type: 'group',
+			label: target.label,
+			filePath: target.filePath || '',
+			icon: '',
+			children: [{ ...target, indent: 1 }, { ...dragged, indent: 1 }],
+			collapsed: false,
+			indent: target.indent,
+		};
+
+		// Replace target with the new group
+		targetInfo.parent.splice(targetInfo.idx, 1, newGroup);
+
+		this.plugin.saveWaypointData();
+		this.redraw();
+	}
+
 	private moveBookmarkToPosition(draggedId: string, targetId: string, before: boolean): void {
 		// Find and remove the dragged item from wherever it is
 		const removeById = (items: BookmarkItem[]): { item: BookmarkItem | null; parent: BookmarkItem[] } => {

styles.css

@@ -159,9 +159,7 @@
 	border-radius: 6px;
 	position: relative;
 	width: 100%;
-	display: flex;
-	align-items: center;
-	justify-content: center;
+	vertical-align: middle;
 }
 
 .waypoint-calendar .waypoint-day:hover {