Importing profiles can lead to errors when forgetting to reconfigure the desired local folder to sync

### Which version of floccus are you using?

`floccus-5.7.0.xpi`

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

⪆ 425

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

~~~JSON
"identity.fxaccounts.enabled": true
~~~

### Sync method

Google Drive

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

Created in `firefox-142.0.1-1.fc42.x86_64.rpm`. Imported into `chromium-139.0.7258.138-1.fc42.x86_64.rpm` (with `chromium-common-139.0.7258.138-1.fc42.x86_64.rpm`).

### Describe the Bug

When [my new `floccus.export.json`][2] is imported into [`floccus-build-v5.7.0.crx`][4], I see: [^2]

[^2]: [`stackoverflow.com/revisions/14099762/4`][6]

[6]: https://stackoverflow.com/revisions/14099762/4#:~:text=https://clients2.google.com/service/update2/crx?response=redirect%26prodversion=%5BPRODVERSION%5D%26acceptformat=crx2%2Ccrx3%26x=id%253D%5BEXTENSIONID%5D%2526uc,the%20ID%20of%20the%20extension

[4]: https://clients2.google.com/service/update2/crx?response=redirect&prodversion=139.0.7258.138&acceptformat=crx2,crx3&x=id%3Dfnaicdffflnofjppbagibeoednhnbjhg%26uc

[2]: https://gist.github.com/RokeJulianLockhart/e6e9891a351b68ca744875a48b932b65#file-floccus-export-json

The exported log states:

~~~B
2025-09-01T18:11:16.252Z Starting sync process for account Google Drive: bookmarks.xbel
2025-09-01T18:11:16.259Z onSyncStart: begin
2025-09-01T18:11:18.319Z onSyncStart: completed
2025-09-01T18:11:18.320Z Using "merge default" strategy (no cache available)
2025-09-01T18:11:18.320Z using the following HashSettings: {"preserveOrder":true,"hashFn":"xxhash3"}
2025-09-01T18:11:18.320Z Retrieving local tree
2025-09-01T18:11:18.321Z Syncing failed with E038: Could not find local folder
2025-09-01T18:11:18.321Z onSyncFail
~~~

For comparison, [`floccus-5.7.0.xpi`][3] has produced the logs that are available at [`gist.github.com/RokeJulianLockhart/0c189a3e58d48ccf5deb9ef9f4385fcc`][1]. This is without importation, which succeeds.

However, when imported (as [`gitlab.com/-/snippets/4884753`][5] [^1] hopefully demonstrates, but which the undermentioned undoubtedly does), automatic synchronisation is impossible to enable:

https://github.com/user-attachments/assets/d330c4d3-f883-43fa-b4df-c0cad9d9565f

[5]: https://gitlab.com/-/snippets/4884753

[^1]: [`github.com/orgs/community/discussions/171958`][6]

[6]: https://github.com/orgs/community/discussions/171958#discussion-8829316

I don't know whether its cause is separate, but the symptom appears related. I can file another issue.

[3]: https://addons.mozilla.org/firefox/downloads/file/4565831/floccus-5.7.0.xpi

[1]: https://gist.github.com/RokeJulianLockhart/0c189a3e58d48ccf5deb9ef9f4385fcc#file-floccus-5-7-0-2025-09-01-full-log

### Expected Behavior

A new profile shouldn't be unusably broken.

### To Reproduce

#### Successful Creation in Firefox

1. ~~~sh
#!/usr/bin/env sh
sudo dnf5 install firefox-142.0.1-1.fc42.x86_64 && \
firefox 'https://addons.mozilla.org/firefox/downloads/file/4565831/floccus-5.7.0.xpi' && \
firefox "moz-extension://$internal_uuid/dist/html/options.html#/options/17567562041690.49589520217880956:~:text=Auto%2Dsync"
~~~

1. At `dist/html/options.html#/:~:text=No%20profiles%20yet`, create a new profile.

1. At `dist/html/options.html#/new:~:text=Google%20Drive`, choose Google Drive.

1. Successfully authenticate, via OAuth2.

1. Choose no name for the profile.

1. Select "Untitled Directory" (the root, `/`). To demonstrate, if this were a filesystem directory, `tree -L 1 .` would return:

~~~MA
/
├── Bookmarks Menu
├── Bookmarks Toolbar
├── Mobile Bookmarks
└── Other Bookmarks

5 directories, 0 files
~~~

1. Export the profile to `floccus.export.json`.

#### Unsuccessful Importation In Chromium

1. ~~~sh
#!/usr/bin/env sh
sudo dnf5 install chromium-139.0.7258.138-1.fc42.x86_64 && \
chromium-browser 'https://clients2.google.com/service/update2/crx?response=redirect&prodversion=139.0.7258.138&acceptformat=crx2,crx3&x=id%3Dfnaicdffflnofjppbagibeoednhnbjhg%26uc'
~~~

1. Import `floccus.export.json`.

1. ~~~sh
#!/usr/bin/env sh
chromium-browser 'chrome-extension://fnaicdffflnofjppbagibeoednhnbjhg/dist/html/options.html#/'
~~~

This reports the aforementioned: that the directory is impossible to locate.

#### Unsuccessful Reimportation in Firefox

1. Import `floccus.export.json`.

1. Synchronise.

### Debug log provided

- [x] I have provided a debug log file