add modalities config for Qwen3-VL-8B-Instruct to enable image input

opencode.json

@@ -13,7 +13,11 @@
           "id": "Qwen3-VL-8B-Instruct",
           "name": "Qwen3-VL-8B-Instruct",
           "limit": { "context": 32768, "output": 8192 },
-          "cost": { "input": 0, "output": 0 }
+          "cost": { "input": 0, "output": 0 },
+          "modalities": {
+            "input": ["text", "image"],
+            "output": ["text"]
+          }
         }
       }
     }