Vault version 999 is unsupported

### Please agree to the following

- [X] I have searched [existing issues](https://github.com/cryptomator/cryptomator/issues?q=) for duplicates
- [X] I agree to follow this project's [Code of Conduct](https://github.com/cryptomator/cryptomator/blob/develop/.github/CODE_OF_CONDUCT.md)

### Summary

Error message “999” appears when attempting to open a vault in iOS Files app

### What software is involved?

- Operating System: iOS 17.5 (21F5058e)
- Cryptomator: 2.5.2 (1228)
- OneDrive: 15.10.3

### Volume Type

None

### Steps to Reproduce

1. Go to Cryptomator app
2. Attempt to open desired vault
3. Error message appears (see ”Actual behavior“)

### Expected Behavior

I expected the vault to open, as it did in the past.

### Actual Behavior

An error message appears. It suggests that I may be using an incorrect version of Cryptomator, and/or that my vault was created with an incompatible version.

> Vault version 999 is unsupported. This vault has been created with an older or newer version of Cryptomator.


### Reproducibility

Always

### Relevant Log Output

_No response_

### Anything else?

_No response_