Add an "Image Inpaint" mode to the MiniMax H3 Director with an optional
internal_execute path (clip/vae/seed inputs, prompt/extra_pnginfo hidden)
so the timeline can drive native inpaint execution in-node. Add
helper_media_output.publish_media_output to route images/video/audio through
the existing saver nodes, and helper_minimax_h3_director_execute for the
Director-owned inpaint execution + postprocess recipe. Extend JS + tests.