fix: KsDataGrid - add retry logic to Enter key edit mode like focusRow

- Apply same ensureEditMode retry pattern to onCellKeyDown
- Retry startEditingCell at 0ms, 10ms, 50ms after tabToNextCell
- Ensures next cell enters edit mode reliably after Enter key

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

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