[bug] No longer able to use symlink for model directory

### Component

not sure

### What happened?

Normally I use a symlink for the huggingface hub because the model directory is quite large. In the last release the symlink is not recognized:

2026-05-30T13:59:48-0700 warning darkbloom.ModelScanner.Discovery: [ProviderCore] Failed to read cache directory /Users/MYUSERNAME/.cache/huggingface/hub: The file “hub” couldn’t be opened.

### Expected behavior

Darkbloom would use the symlink like it normally does.

### Steps to reproduce

Install 0.5.14
Symlink ~/.cache/huggingface to a folder somewhere else
Darkbloom start

### Environment

darkbloom 0.5.14
Mac Ultra M1 128GB
MacOS 26.5

### Logs

```shell

```

### Confirmations

- [x] I searched existing issues and this isn't a duplicate

Start by reproducing the issue with Darkbloom 0.5.14 on macOS: symlink ~/.cache/huggingface to another folder, then launch Darkbloom and inspect the reported cache-directory warning. No source file or test is named, so trace the model-cache discovery path from that log message. Done means the symlinked Hugging Face cache is read successfully.

Written by the indexing model from the issue text.