Cannot Copy `.rtfd` Package Files into Vault

### Summary

Copying or moving `.rtfd` files into a vault via the Files app fails with the error "The file doesn't exist."

### Please agree to the following

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

### System Setup

- iOS: 26.1
- Cryptomator: 2.7.3

### Cloud Type

_No response_

### Steps to Reproduce

1. In the Files app, create or obtain an `.rtfd` file (e.g., created with TextEdit on macOS).
2. Attempt to copy or move the `.rtfd` file into the vault.

### Expected Behavior

The `.rtfd` file should be copied or moved into the Cryptomator vault without errors.

### Actual Behavior

The operation fails with the message:

> **The file doesn't exist.**
> The file "X" couldn't be copied because it either doesn't exist or the folder it is being copied to doesn't exist.

### Reproducibility

Always

### Relevant Log Output

_None_

### Anything else?

`.rtfd` documents are macOS/iOS packages (directory bundles), not single files, which may contribute to the issue.

Start by reproducing the `.rtfd` copy or move from the iOS Files app into a vault, then trace the vault's file-copy handling for directory bundles. Done means an `.rtfd` package can be copied or moved into the vault without the reported “The file doesn't exist” error.

Written by the indexing model from the issue text.