Calibrate a similarity threshold from corpus embeddings via useCalibrateThreshold at percentile 90, over a selected embedding model and corpus, rendering the calibrated threshold versus the model's getDefaultThreshold preset, metadata, distribution statistics, and the MODEL_THRESHOLD_PRESETS reference with the selected model highlighted. The provider-prefixed model id is normalized so the panel, preset highlight, and presets reference align. The model downloads only behind Calibrate. No model bytes download until an explicit in-block action.