bf04a12b89
customNodeFetch previously used res.setEncoding('utf8') and concatenated
chunks into a string. This corrupted JPEG/PNG binary data with UTF-8
replacement characters, causing Gemini to return:
400 Unable to process input image.
Now chunks are collected as Buffers and concatenated, preserving binary
integrity when images are fetched from presigned S3 URLs before being
sent to Gemini.