fix: Remove duplicate OpenAI models from listmodels output

Fixed issue where OpenAI models appeared twice in listmodels output by:
- Removing self-referencing aliases from OpenAI model definitions (e.g., "gpt-5" no longer includes "gpt-5" in its aliases)
- Adding filter in listmodels.py to skip aliases that match the model name
- Cleaned up inconsistent alias naming (o3-pro -> o3pro)

This ensures each model appears only once in the listing while preserving all useful aliases.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tools/listmodels.py

@@ -138,7 +138,9 @@ class ListModelsTool(BaseTool):
                 for model_name, capabilities in provider.get_model_configurations().items():
                     if capabilities.aliases:
                         for alias in capabilities.aliases:
-                            aliases.append(f"- `{alias}` → `{model_name}`")
+                            # Skip aliases that are the same as the model name to avoid duplicates
+                            if alias != model_name:
+                                aliases.append(f"- `{alias}` → `{model_name}`")
 
                 if aliases:
                     output_lines.append("\n**Aliases**:")