Keep TEST-s composer test aligned with button label

The TEST-s branch renders the composer generate action with the English aria-label used by nearby tests. Updating the stale assertion keeps the test focused on image-count persistence instead of locale-specific text.

Constraint: TEST-s currently renders the generate button aria-label as Generate in this test setup
Rejected: Change composer runtime label for the test | would alter UI behavior to satisfy a stale assertion
Confidence: high
Scope-risk: narrow
Directive: Prefer stable accessible labels already used in adjacent composer tests
Tested: npm run test:run -- src/components/__tests__/GenerateImageNode.test.tsx src/components/__tests__/GenerationComposer.test.tsx src/app/api/generate/providers/__tests__/newapiwg.test.ts
Tested: git diff --check
Not-tested: Full browser locale sweep

src/components/__tests__/GenerationComposer.test.tsx

@@ -498,7 +498,7 @@ describe("GenerationComposer", () => {
     fireEvent.change(screen.getByRole("textbox"), {
       target: { value: "new root image candidates" },
     });
-    fireEvent.click(screen.getByLabelText("生成"));
+    fireEvent.click(screen.getByLabelText("Generate"));
 
     await waitFor(() => {
       expect(useWorkflowStore.getState().regenerateNode).toHaveBeenCalled();