Cannot select SD card folder when creating new Auto Upload rule

### ⚠️ Before posting ⚠️

- [x] This is a **bug**, not a question or an enhancement.
- [x] I've [searched for similar issues](https://github.com/nextcloud/android/issues) and didn't find a duplicate.
- [x] I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/).

### Steps to reproduce

Open Nextcloud Android app.
Go to Settings → Auto Upload.
Add a new Auto Upload folder.
Choose a local folder.
Try to navigate to a folder located on the SD card.

### Expected behaviour

Cannot select SD card folder when creating new Auto Upload rule (Android 16 / One UI 8.5)
Description

Since updating to Nextcloud Android app 34.1.0-beta (Google Play release updated on 23 July 2026), I cannot create new Auto Upload rules targeting folders on the SD card.

Existing Auto Upload configurations pointing to the SD card still work correctly. Manual uploads from the SD card also work. The issue only affects the creation of new Auto Upload folder mappings.

Environment
Nextcloud Android app: 34.1.0-beta
Installation source: Google Play
Android version: Android 16
Device: Samsung Galaxy A55
UI: One UI 8.5
SD card type: Portable storage
Steps to reproduce
Open Nextcloud Android app.
Go to Settings → Auto Upload.
Add a new Auto Upload folder.
Choose a local folder.
Try to navigate to a folder located on the SD card.
Expected behavior

The SD card should be accessible and allow selecting a folder as the local source for a new Auto Upload rule.

Actual behavior
The SD card appears in the folder selector.
It cannot be opened/selected.
The folder list remains limited to internal storage folders.
The app becomes unresponsive/frozen during this action.
No error message is displayed.
Additional information
Existing Auto Upload links using SD card folders continue to work.
Manual upload from SD card works normally.
App cache was cleared.
Permissions were checked and are correctly granted.
The issue is reproducible every time using the steps above.

This looks like an issue specific to the folder picker used when creating a new Auto Upload configuration, rather than a general SD card access problem.

### Actual behaviour

App freeze

### Android version

16

### Device brand and model

Galaxy A55

### Stock or custom OS?

Stock

### Nextcloud android app version

34.1.0

### Nextcloud server version

.

### Using a reverse proxy?

I don't know

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_

Start by reproducing the issue through Settings → Auto Upload → Add a new Auto Upload folder, then inspect the folder picker used for choosing a local folder. Done means an SD card folder can be opened and selected for a new Auto Upload rule without the app freezing; existing SD card uploads should remain unaffected.

Written by the indexing model from the issue text.