Cannot read properties of undefined (reading 'filter')

### Which version of floccus are you using?

5.8.0

### How many bookmarks do you have, roughly?

5k

### Are you using other means to sync bookmarks in parallel to floccus?

No

### Sync method

Git

### Which browser are you using? In case you are using the phone App, specify the Android or iOS version and device please.

Brave 1.84.141

### Which version of Nextcloud Bookmarks are you using? (if relevant)

_No response_

### Which version of Nextcloud? (if relevant)

_No response_

### What kind of WebDAV server are you using? (if relevant)

_No response_

### Describe the Bug

Getting Cannot read properties of undefined (reading 'filter') error when trying to sync
[floccus-5.8.0-2025-12-08-full (2).log](https://github.com/user-attachments/files/24036508/floccus-5.8.0-2025-12-08-full.2.log)

### Expected Behavior

Syncing successfully without an error

### To Reproduce

Just sync

### Debug log provided

- [x] I have provided a debug log file