Fix agent error handling for 404 nutrition service responses

[github-actions]

Summary

This PR fixes the critical issue where AI agents were fabricating non-existent products when the nutrition service returned 404 errors for unsupported pet types.

Problem

The investigation revealed that:

• Missing pet types: rabbit (1,760 404 errors), ferret (294 errors), guinea pig (268 errors), turtle (227 errors), bearded dragon (123 errors)
• Current database only contains: cat, dog, lizard, snake, bird, hamster
• Total 404 errors: 6,401 requests for missing pet nutrition data
• AI agents were fabricating products when nutrition service returns 404

Changes Made

1. Enhanced Nutrition Agent Error Handling (nutrition_agent.py)

• Proper 404 detection: Added explicit handling for response.status_code == 404
• Clear error messaging: Responds with "I don't have nutrition information for [pet type] pets" instead of fabricating products
• Supported pet types listing: Clearly states which pet types are supported (cats, dogs, birds, hamsters, lizards, snakes)
• Validation for product recommendations: Prevents product recommendations when nutrition service returns 404
• Improved system prompt: Added critical instruction to NEVER fabricate product names or recommendations

2. Enhanced Primary Agent Error Handling (pet_clinic_agent.py)

• Better error propagation: Improved handling of nutrition specialist unavailability messages
• Cleaner error responses: More user-friendly messages when nutrition information is not available
• Updated system prompt: Added guidance for handling unsupported pet types gracefully

Key Improvements

✅ Prevents AI hallucination of non-existent products
✅ Clear error messaging for unsupported pet types
✅ Graceful degradation when nutrition service is unavailable
✅ Maintains user experience by providing helpful alternatives
✅ Explicit validation before making product recommendations

Testing

The fix addresses the root cause identified in the investigation:

• Agents now properly handle 404 responses from nutrition service
• No more fabricated product recommendations for unsupported pet types
• Clear messaging guides users to contact veterinarian for unsupported pets
• Maintains functionality for supported pet types (cats, dogs, birds, hamsters, lizards, snakes)

Related Issue

Fixes the agent error handling issue identified in the Application Signals investigation showing 6,401 404 errors and AI agent fabrication of non-existent products.