LoRA training freed VRAM with unload_all_models(), which only unloads THIS
engine's models. On the GGUF-isolation split the co-located gguf (text) engine
kept its model resident (~7.4 GB), so fp32 training (~16 GB) + the sibling
exceeded the 24 GB card → "CUDA out of memory. Tried to allocate 32 MiB … 26 MiB
free … Process 226 has 7.36 GiB" — every fighter LoRA (dlaba, zigo, zlo, …)
failed. Training also isn't covered by the front swap-gate, so nothing else
cleared the sibling.

Add multi_model_manager.evict_cosited_siblings(): invoke the registered
cross-engine VRAM releasers (the cosite releaser posts wait=True, so it waits for
a busy sibling to reach a safe point). Call it right after unload_all_models() in
both training paths (image + video/Wan), so training gets the whole card.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RdMufYvtTbtGDWsiZVoXce