Stop the capture script seeding a node into a populated flow

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H7LwYgJfpkbLCTeiAf8U4A

frontend/scripts/capture-screenshots.mjs

@@ -117,6 +117,13 @@ async function captureFlows(page, dir) {
     await page.getByTestId("create-flow").click()
   }
   await page.waitForURL(/\/flows\/.+/, { timeout: 15000 })
+  // The canvas paints before the flow detail arrives, so counting nodes right
+  // away reads 0 for a populated flow — and the seeding below would then add a
+  // node to somebody's real flow. Wait until it says which of the two it is.
+  await page
+    .locator(".react-flow__node, [data-testid=flow-empty]")
+    .first()
+    .waitFor({ timeout: 15000 })
 
   if (!(await page.locator(".react-flow__node").count())) {
     await page.getByTestId("add-node").click()

frontend/src/components/Flow/FlowEditor.tsx

@@ -984,7 +984,10 @@ function FlowEditorInner({
       </div>
 
       {definitions.length === 0 ? (
-        <div className="pointer-events-none absolute inset-0 flex items-center justify-center">
+        <div
+          className="pointer-events-none absolute inset-0 flex items-center justify-center"
+          data-testid="flow-empty"
+        >
           <div className="flex flex-col items-center gap-3 text-center">
             <span className="flex size-14 items-center justify-center rounded-full bg-muted text-muted-foreground">
               <Workflow className="size-6" />