Fills the gap flux_local can't (mflux is FLUX-only). Pure-stdlib run.py talks
to a resident ComfyUI on :8188 (auto-starts, keeps checkpoints cached — 4s
warm per 5122/20-step image on M3). Warns on the SD1.5-LoRA-on-SDXL trap.
No manifest python => uses the node's system python3 via the python-less
remote path, so it distributes across the gpu pool.
