Function unpack_fused_output 

pub fn unpack_fused_output<P: Profile>(
    frame: &FusedFrame<P>,
) -> Result<(Signature<P>, PublicKey<P>), OutputFrameError>

Validates and unpacks a canonical fused-output stream.

Strict validation catches misplaced last, malformed keep masks, and nonzero data in invalid final lanes. This makes byte-order mistakes visible in simulation instead of accepting an equivalent-length but ambiguous frame.

Errors

Returns OutputFrameError when any keep mask, last marker, or invalid padding lane differs from the canonical 35-beat representation.