fix: KsDataGrid - simplify Enter key handler, rely on AG Grid tabToNextCell

- Remove redundant startEditingCell calls that override AG Grid native behavior
- Use only stopEditing + tabToNextCell with setTimeout
- Let AG Grid handle edit mode auto-start for next cell

frontend/src/shared/ui/components/KsDataGrid.vue

@@ -116,18 +116,10 @@ function onCellKeyDown(event: any): void {
   if (event.event.key === 'Enter' && event.colDef?.editable) {
     event.event.preventDefault()
     event.api.stopEditing(false)
-    event.api.tabToNextCell(false)
 
-    const ensureEditMode = () => {
-      const focusedCell = event.api.getFocusedCell()
-      if (focusedCell) {
-        event.api.startEditingCell(focusedCell)
-      }
-    }
-
-    ensureEditMode()
-    setTimeout(ensureEditMode, 10)
-    setTimeout(ensureEditMode, 50)
+    setTimeout(() => {
+      event.api.tabToNextCell(false)
+    }, 0)
   }
 }