OSEC-2026-12 AEAD `decrypt_into` functions writes plaintext before checking the tag

On the generic GCM path, AES.GCM.authenticatedecryptinto as well as Chacha20.authenticatedecryptinto and AES.CCM16.authenticatedecryptinto writes the decrypted plaintext into the caller's destination buffer and only then compares the tag. On a forged tag the function returns false, but the...