#3216 [GUI] Control Vector arguments are removed when loading a model

Description

## Description

I'm experiencing an issue with **Control Vector arguments in the new Strata Desktop GUI**.

I use **Expert Mode** and its **JSON editor** to manually add the Control Vector parameters directly inside the existing `"args": [...]` array of my model configuration.

The JSON syntax is valid, and the arguments are placed in the correct section.

However, every time I click **Load Model**, Strata regenerates the JSON configuration and removes the Control Vector arguments.

**Other model settings appear to persist correctly. The issue seems specific to Control Vector arguments.**

## Steps to reproduce

1. Open Strata Desktop.
2. Select an installed model.
3. Switch to **Expert Mode**.
4. Open the **JSON editor**.
5. Add the following arguments inside the existing `"args": [...]` array:

```json
"--control-vector-scaled",
"C:\\path\\to\\control-vector.gguf:1.0",
"--control-vector-layer-range",
"4",
"44",
"--cvec-mode",
"project",
"--cvec-dir",
"per-layer"
```

6. Save the JSON configuration.
7. Click **Load Model**.
8. Reopen the JSON configuration.

## Actual behavior

The configuration is regenerated, and the Control Vector arguments disappear from the `"args"` array.

Other model parameters appear to be preserved.

Consequently, the model starts without the requested Control Vector configuration.

## Expected behavior

Control Vector arguments entered through **Expert Mode > JSON** should be preserved when loading or reloading a model.

Since the engine already supports these arguments, I would expect the Desktop GUI to retain them in the generated configuration.

## Suggested improvement

Ideally, the Desktop GUI should either:

- Preserve Control Vector arguments entered through Expert Mode.
- Provide dedicated Control Vector settings in the advanced model configuration.

## Environment

- **Strata Desktop:** 0.2.0-beta
- **Engine:** 0.1.45.3
- **OS:** Windows 11
- **GPU:** NVIDIA RTX 5080, 16 GB VRAM
- **RAM:** 64 GB

## Additional information

The same Control Vector arguments worked with my previous standalone Strata installation.

I would prefer to keep using the new Desktop GUI rather than switching to the CLI/TUI.

Is this the intended behavior of Expert Mode, or should Control Vector arguments be preserved when the GUI regenerates the model configuration?

Thanks for your work on Strata <3 !