Pane header create button renders intent and params as DOM attributes while template permissions load #15035

Describe the bug

In development, opening a document list whose pane header shows a single create button logs two styled-components warnings:

styled-components: it looks like an unknown prop "intent" is being sent through to the DOM, which will likely trigger a React console error. […]
styled-components: it looks like an unknown prop "params" is being sent through to the DOM, which will likely trigger a React console error. […]

On the first render the button is an anchor that carries both props as attributes:

<a data-testid="action-intent-button" role="link" aria-disabled="true" intent="create" params="[object Object]">

Once the template permissions resolve, it is replaced by the regular IntentLink (href="/intent/create/template=author;type=author/", no intent or params attribute), so the leak lasts only for the loading render.

The disabled branch of the core IntentButton spreads every prop into the anchor (IntentButton.tsx#L14-L15):

return props.disabled ? (
  <Button {...props} as="a" role="link" aria-disabled="true" />

PaneHeaderCreateButton passes the intent into it as spread props (#L123), and the button is disabled while useTemplatePermissions is still loading (const disabled = !permissions?.granted, #L112). This started with #14226, which replaced the structure-local IntentButton (it destructured intent before spreading the rest) with the core one.

To Reproduce

A Studio with nothing but the structure tool is enough:

// sanity.config.ts
import {defineConfig} from 'sanity'
import {structureTool} from 'sanity/structure'

export default defineConfig({
  projectId: '<projectId>',
  dataset: '<dataset>',
  plugins: [structureTool()],
  schema: {
    types: [{name: 'author', type: 'document', fields: [{name: 'name', type: 'string'}]}],
  },
})

1. Install sanity@6.15.0, react@19.3.0, react-dom@19.3.0 and styled-components@6.5.3, then run sanity dev.
2. Open /structure/author.
3. See both warnings in the browser console.

With the same setup on sanity@6.9.2 the warnings do not appear. The code is unchanged in 6.16.0 and on main (6619338).

Expected behavior

No unknown-prop warnings: the disabled create button renders its anchor without the IntentLink-only props such as intent and params.

Which versions of Sanity are you using?

@sanity/cli (global)  8.12.0 (latest: 8.13.0)
sanity                6.15.0 (latest: 6.16.0)

What operating system are you using?

macOS 26.6.2, Chrome 154

Which versions of Node.js / npm are you running?

Node.js 24.20.0, pnpm 11.27.1

Additional context

Reproduced both in a Next.js 16.3 app with an embedded Studio (next-sanity 13.3.4) and in the standalone setup above.