Bun preset doesn't work for TanStack Start `createFileRoute` $ API endpoints

[jonasfroeller]

Environment

Dynamic API endpoints created using createFileRoute in TanStack Start are not being registered when using the Bun preset. All API route requests return 404 errors instead of executing the defined handlers.

Reproduction

1. Make a $ route:

example:

import { createFileRoute } from '@tanstack/react-router'
import { reactStartHandler } from '@convex-dev/better-auth/react-start'

export const Route = createFileRoute('/api/auth/$')({
  server: {
    handlers: {
      GET: ({ request }) => {
        return reactStartHandler(request)
      },
      POST: ({ request }) => {
        return reactStartHandler(request)
      },
    },
  },
})

2. Build using preset:

plugins.push(nitro({ preset: 'bun' }))

Describe the bug

All API route requests return 404 errors instead of executing the defined handlers.

Additional context

"nitro": "3.0.1-alpha.1",

bun --version
1.3.2

Logs

none

[pi0]

Appreciate if you can share a runnable minimal tanstack+nitro reproduction (no other deps)