feat(models): add GPT-5.5 to the registry with support for advanced tasks

internal/registry/models/models.json

@@ -1293,6 +1293,29 @@
         ]
       }
     },
+    {
+      "id": "gpt-5.5",
+      "object": "model",
+      "created": 1776902400,
+      "owned_by": "openai",
+      "type": "openai",
+      "display_name": "GPT 5.5",
+      "version": "gpt-5.5",
+      "description": "Frontier model for complex coding, research, and real-world work.",
+      "context_length": 272000,
+      "max_completion_tokens": 128000,
+      "supported_parameters": [
+        "tools"
+      ],
+      "thinking": {
+        "levels": [
+          "low",
+          "medium",
+          "high",
+          "xhigh"
+        ]
+      }
+    },
     {
       "id": "codex-auto-review",
       "object": "model",