feat: Sanitize logging for image modality

[wprazuch]

When running MMMU Pro, the logging from Caching Interceptor congests the stdout with base64 encoded strings of characters. This makes logging, and progress following of image-based harnesses impossible to investigate and track.

After this fix, the stdout is now clear and readable:

[I 2026-02-04T17:47:50.737] 127.0.0.1 - - [04/Feb/2026 17:47:50] "POST /chat/completions HTTP/1.1" 200 -
[I 2026-02-04T17:47:50.745] Request started path=chat/completions method=POST url=https://inference-api.nvidia.com/v1/chat/completions logger=root request_id=e3c17a10-995e-4e1e-8c02-2d56f3b1feb8 model_name=gcp/google/gemini-2.5-flash
[D 2026-02-04T17:47:50.752] Intercepted request request_data={'messages': [{'role': 'user', 'content': [{'type': 'image_url', 'image_url': {'url': '<image: format=png, size≈385128 bytes>'}}, {'type': 'text', 'text': "Answer the following multiple choice question. The last line of your response should be in the following format: 'Answer: A/B/C/D/E/F/G/H/I/J' (e.g. 'Answer: A').\n\n\n\nA) A memory\nB) A transition\nC) An opportunity\nD) A common experience\nE) A journey\nF) A warning\nG) A clock\nH) Time waits for no man\nI) An obstacle\nJ) A mystery"}]}], 'model': 'gcp/google/gemini-2.5-flash', 'frequency_penalty': 0.0, 'logprobs': False, 'n': 1, 'presence_penalty': 0.0, 'seed': 0, 'temperature': 0.0, 'top_p': 0.95, 'min_p': 0.0, 'repetition_penalty': 1.0, 'spaces_between_special_tokens': False} logger=CachingInterceptor request_id=e3c17a10-995e-4e1e-8c02-2d56f3b1feb8 model_name=gcp/google/gemini-2.5-flash
[D 2026-02-04T17:47:50.752] Processing request for caching cache_key=c07bd66a... request_data_keys=['messages', 'model', 'frequency_penalty', 'logprobs', 'n', 'presence_penalty', 'seed', 'temperature', 'top_p', 'min_p', 'repetition_pe

Note the {'type': 'image_url', 'image_url': {'url': '<image: format=png, size≈385128 bytes>'}}, sanitized description of the input.

[agronskiy]

Cann image (the capturing group) be empty?

[wprazuch]

[^;]+ denotes one or more characters, so it cannot be empty.

Not that I know this, Cursor told me 😆

[copy-pr-bot]

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[wprazuch]

/ok to test 3f572a8