CAP never authorizes.

Strict Ed25519 verification boundary for already-framed protocol bytes.

Before invoking OTP crypto, this module rejects noncanonical point encodings, the complete eight-point torsion set for both the public key and R, and scalars outside the canonical subgroup-order range. This prevents low-order universal forgeries that the raw runtime primitive can accept. The module accepts only public verification material. It never signs, selects trust, or authorizes an artifact.