Data model: chainId and keyId

[immortal-tofu]

• A coprocessor listens to events from multiple chains (Ethereum, Base, Shiba, etc.). We refer to these chains by their unique chain ID.
• A coprocessor computes using a single key, identified with a key ID, shared across all chains.
• A ciphertext is associated with a key ID. If a computation is performed using a previously used key ID, the coprocessor provides the key switch key to tfhe-rs to update the ciphertext before the computation.

[rudy-6-4]

Maybe add how tenant id relates to chain id, and key id.
E.g. one tenant id can operates on several chain id, one tenant id has only 1 key shared by many tenant id, ...

[immortal-tofu]

Maybe add how tenant id relates to chain id, and key id. E.g. one tenant id can operates on several chain id, one tenant id has only 1 key shared by many tenant id, ...

tenant id = chain id AFAIU