Model directory change in Settings is not saved or applied

[trigger2k20]

Describe the bug
Changing the model directory in the Settings dialog does not persist when using Save and/or closing the dialog. The configured path remains unchanged, and the application continues to use the default model directory.
As a workaround, the setting must be edited manually in settings.json at:

/Users/username/.omlx/settings.json

Default value:
"model": {
"model_dirs": [
"/Users/username/.omlx/models"
],
"model_dir": "/Users/username/.omlx/models",
"max_model_memory": "auto",
"model_fallback": false
}

Working manual modification for path "/Volumes/big2/modelstorage/llm":

"model": {
"model_dirs": [
"/Volumes/big2/modelstorage/llm"
],
"model_dir": "/Volumes/big2/modelstorage/llm",
"max_model_memory": "auto",
"model_fallback": false
}

To Reproduce
Steps to reproduce the behavior:

1. Open the application.
2. Go to Settings.
3. Navigate to the model storage / model directory setting.
4. Change the model directory to a different path, for example /Volumes/big2/modelstorage/llm.
5. Click Save and/or close the Settings dialog.
6. Reopen Settings or inspect the effective configuration.
7. Observe that the model directory change was not applied or persisted.

Expected behavior
The updated model directory should be saved correctly when pressing Save or closing the Settings dialog, and the application should immediately use the new path without requiring manual modification of settings.json.

Screenshots
not applicable

Desktop (please complete the following information):
OS: macOS 26 or later
Browser: any browser
Version: 0.3.5-rc1 Build: 260415010848-macos26-tahoe

Additional context
The issue appears to be limited to the Settings UI not writing the updated values back to the configuration file.