Ask for the name in a dialog instead of a field that is always there

Create in both overviews now opens a dialog, so the toolbar is a search box
and one button. The specs and the capture script open it first.

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

frontend/tests/flows.spec.ts

@@ -73,6 +73,7 @@ test("a flow can be created, wired up, and comes back after a reload", async ({
   await page.goto("/flows")
 
   // Create a flow of our own so the test does not lean on existing data.
+  await page.getByTestId("new-flow").click()
   await page.getByTestId("new-flow-name").fill(flowName)
   await page.getByTestId("create-flow").click()
   await page.waitForURL(`/flows/${flowName}`)