Upload processor_config.json

## Fix: Add missing `spatial_merge_size` to processor config

### Problem

Missing `spatial_merge_size` parameter causes vision inference to crash:
ValueError: Number of image token positions (5476) does not match number of image features (1369)

### Solution

Add `"spatial_merge_size": 2` to `processor_config.json`:

```json
{
"image_break_token": "[IMG_BREAK]",
"image_end_token": "[IMG_END]",
"image_token": "[IMG]",
"patch_size": 14,
"processor_class": "PixtralProcessor",
"spatial_merge_size": 2
}

This matches the original https://huggingface.co/mistralai/Mistral-Small-3.1-24B-Instruct-2503/blob/main/processor_config.json and config.json.

✅ Tested on M2 Max 64GB - vision inference works after fix.

Same fixes needed for: -4bit, -6bit, -8bit, -bf16 (all 0.1.19 conversions)
```

processor_config.json

@@ -3,5 +3,6 @@
   "image_end_token": "[IMG_END]",
   "image_token": "[IMG]",
   "patch_size": 14,
-  "processor_class": "PixtralProcessor"
+  "processor_class": "PixtralProcessor",
+  "spatial_merge_size": 2
 }