Add sample for structured "imagination"

[leloykun]

"Structured Imagination" is a placeholder name for controlling how many "draft" tokens and "imagination" tokens the model generates first before generating the final answer.

Sample json schema:

json_schema = {
    "name": "Fruit Generator",
    "description": "A tool that generates details about a fruit with text and images in one go!",
    "type": "object",
    "properties": {
        "imagination" : {
            "type": "image",
            "maxLength": 100,
        },
        "draft_reasoning": {
            "type": "string",
            "pattern": "[a-zA-Z0-9]{1,100}",
        },
        "imagination_2" : {
            "type": "image",
            "maxLength": 100,
        },
        "draft_reasoning_2": {
            "type": "string",
            "pattern": "[a-zA-Z0-9]{1,100}",
        },
        "cat_dog": {
            "type": "image",
        }
    },
    "required": ["imagination", "draft_reasoning", "imagination_2", "draft_reasoning_2", "cat_dog"],
}

Equivalent regex expression:

\{[ ]?"imagination"[ ]?:[ ]?"<image>{,100}"[ ]?,[ ]?"draft_reasoning"[ ]?:[ ]?("[a-zA-Z0-9]{1,100}")[ ]?,[ ]?"imagination_2"[ ]?:[ ]?"<image>{,100}"[ ]?,[ ]?"draft_reasoning_2"[ ]?:[ ]?("[a-zA-Z0-9]{1,100}")[ ]?,[ ]?"cat_dog"[ ]?:[ ]?"<image>{1024,1024}"[ ]?\}