Add support for domain-specific models:

1. ChartAssistant (`chartast.py`)
2. ChartInstruct (`chartinstruct.py`)
3. ChartLlama (`chartllama.py`)
4. CogAgent (`cogagent.py`)
5. DocOwl1.5 (`docowl15.py`)
6. TextMonkey (`textmonkey.py`)
7. TinyChart (`tinychart.py`)
8. UniChart (`unichart.py`)
9. UReader (`ureader.py`)