Finite observation windows for continuous powers of normal operators

Unrefereed AI-assisted research candidate. For a bounded normal operator with a fixed bounded Borel argument, a semi-continuous frame on one finite interval starting at zero remains a frame on every positive finite interval starting at zero. Invertibility, reductivity and Bessel sensors are not assumed. Written proofs and scoped exact/numerical example checks are provided. The existence theorem does not guarantee uniform conditioning, finite sampling or practical performance. Internal AI review and producer replay are not external peer review, independent reproduction or formal verification. The bounded literature search is not proof of historical priority.