- Add 'developer' to accepted role literals in ChatMessage model
- Existing normalization in chat.py converts developer → system before watsonx API call
- Fixes 422 validation errors when clients send developer role messages
- Maintains backward compatibility with all existing roles
- Emphasize that inline comments cause service startup failures
- Show correct .env format without inline comments
- Add example error message when inline comments are present
- Include sed command to fix existing .env files with inline comments
- Add model mapping examples in correct format
- Normalize 'developer' role to 'system' (vLLM doesn't support developer role)
- Flatten array content to string for text-only messages
- Preserve mixed content (text + images) as array
- Add comprehensive unit tests for normalization logic
Fixes HTTP 422 errors when clients send OpenAI multi-content format
