Fingerprint stability when fields are physically created and destroyed in the DOM
Technique: Conditional fields are physically added to and removed from the DOM using appendChild() and removeChild(). When a condition is not met, the field elements do NOT exist in the DOM at all.
Why it matters: This is how React/Vue/Angular conditional rendering works ({showField && <input>}). The framework's virtual DOM reconciliation actually creates/destroys real DOM nodes. Also used by some advanced form builders.
Expected result (STRESS TEST): If the SDK fingerprints the form before conditional fields are added, those fields won't be in the hash. If fingerprinted after, they will be. The cache should prevent re-hashing, but this tests whether the initial fingerprint timing captures the right state.