[ECD5A]

Deoxys-I, Deoxys-II and OCB3 leave unauthenticated plaintext in the output buffer when tag verification fails. Clear the output before returning the authentication error.

The regression tests cover in-place and separate buffers, block boundaries, and modified tags, AAD, nonces and ciphertext.

Validation:

• Reproduced the issue before the fix and confirmed cleanup after it.
• Verified that authenticated ciphertext, tags and plaintext remain unchanged.
• Package tests passed on Windows and Linux, including release/all-features runs.
• Tests also passed on Rust 1.85.1.
• cargo fmt --all -- --check and Clippy with -D warnings passed.

Fixes #888