fix(canvas): start selection title rename on single click

Switch the editable selection title from onDoubleClick to onClick so
renaming a node/layer title begins with a single click.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/ui/pages/CanvasWorkspace/canvas/CanvasSelectionFrame/index.tsx

@@ -149,7 +149,7 @@ function EditableSelectionTitle({
       aria-label={renameLabel}
       title={title}
       onPointerDown={(event) => event.stopPropagation()}
-      onDoubleClick={(event) => {
+      onClick={(event) => {
         event.stopPropagation();
         startEditing();
       }}