feat: add native Anthropic auxiliary vision

tools/vision_tools.py

@@ -3,7 +3,8 @@
 Vision Tools Module
 
 This module provides vision analysis tools that work with image URLs.
-Uses Gemini 3 Flash Preview via OpenRouter API for intelligent image understanding.
+Uses the centralized auxiliary vision router, which can select OpenRouter,
+Nous, Codex, native Anthropic, or a custom OpenAI-compatible endpoint.
 
 Available tools:
 - vision_analyze_tool: Analyze images from URLs with custom prompts
@@ -409,7 +410,7 @@ if __name__ == "__main__":
     
     if not api_available:
         print("❌ No auxiliary vision model available")
-        print("Set OPENROUTER_API_KEY or configure Nous Portal to enable vision tools.")
+        print("Configure a supported multimodal backend (OpenRouter, Nous, Codex, Anthropic, or a custom OpenAI-compatible endpoint).")
         exit(1)
     else:
         print("✅ Vision model available")