[3.0] Protect against chunk reordering and truncation in ChunkedEncryption authentication

[bchess]

Leaving this as placeholder for @Eta0 to make accurate description.
Copying from https://github.com/coreweave/tensorizer/pull/127#pullrequestreview-2133569874https://github.com/coreweave/tensorizer/pull/127#pullrequestreview-2133569874

Tweak ChunkedEncryption slightly in a way that is incompatible with older deserializers, so I'd like to add it in the new data version 5 alongside the changes in this PR

[Eta0]

This is referring to resolving a limitation currently listed in docs/encryption.md:

This level of encryption [ . . . ] does not protect against reordering or truncation of chunks.

We can protect against reordering and truncation of chunks by creating a hash list complete with a top hash. We currently use a hash list that is missing a top hash, so individual chunks of a tensor are verifiable, but their count and positions are not.

A good title for this issue would be "Protect against chunk reordering and truncation in ChunkedEncryption authentication."