- github.js: add sanitizeMessages() to convert unsupported content types (tool_use, tool_result, thinking) to plain text before sending to GitHub /chat/completions endpoint - openai-responses.js: skip pushing message blocks with empty content (e.g. assistant messages that only contain tool_calls) - providerModels.js: revert targetFormat changes (not needed with sanitize fix) Fixes: https://github.com/decolua/9router/issues/219