Fix image dimension validation for multi-image requests in chat history

Discord Message

Author: mani_19291 Channel: #shelley Link: https://discord.com/channels/1405685085923049482/1450334528210993295/1454545623020998772

Hey, I hit this error when trying to send a message with a screenshot attached: LLM request failed: status 400 Bad Request (url=http://169.254.169.254/gateway/llm/_/gateway/anthropic/v1/messages, model=claude-opus-4-5-20251101): {"type":"error","error":{"type":"invalid_request_error","message":"messages.21.content.1.image.source.base64.data: At least one of the image dimensions exceed max allowed size for many-image requests: 2000 pixels"},"request_id":"req_011CWWFKGCBmXvmjmDwnsG7V"}

The screenshot itself wasn't huge at all, so I'm guessing Shelly might be pulling in other images from the chat history like maybe browser tool screenshots or something? Starting a fresh chat worked fine as a workaround. Just wanted to flag it in case there's a way to handle this on the Shelly side.