FLUX.1 [kontext] pro API

Unified FLUX Kontext API access for <strong>flux-kontext-pro</strong>, <strong>flux-kontext-pro-edit</strong>, <strong>flux-kontext-max</strong>, and <strong>flux-kontext-max-edit</strong>. Use one submit endpoint for text-to-image and image editing, choose sizes from <strong>1:1</strong> to <strong>16:21</strong>, and return <strong>png</strong> or <strong>jpg</strong> output.