Add Krea 2 two-image i2i workflows (turbo + raw)

Add Krea 2 workflows (raw/turbo t2i + turbo i2i, optional LoRA placeholder)

Add qwen-edit-turbo-v2.json (full-precision text encoder + 8-step Lightning LoRA)

Add remaining API-format workflows; converter fixes (subgraph promoted inputs, rgthree loras, undeclared seed-control widgets)

Add API scripts (upload/download/run/convert) and API-format headswap workflow