[App & API] Improved Model Swap Consistency

Model Swap now more reliably changes identities, even when the prompt closely resembles the current subject (for example, “a Brazilian woman”).

This update ensures swaps occur as intended, even with similar or missing prompts, while improving attention to extremities such as hands and feet. These areas now adjust more accurately in age or ethnicity swaps, reflecting realistic variations in skin tone and texture across the entire body.