feat(vault): deposit vault, account abstraction and paymaster

[maurerbot]

Why

To bring over the next billion users into blockchain we need to be able to support users who don't want to learn or manage blockchain accounts and wallets. With Rollup, developers can provision a "deposit vault" for users signing up to their application (or allow the users to select an already connected account). Developers should then have an easy way to work with these wallets for their apps/games/etc.

What

A deposit vault will expose some APIs protected by scopes and be treated like a special connected addresses. At first this could just be a read only connected account so we may be able to allow users to select from a list of already connect blockchain accounts to use a a deposit vault.

To deposit items into this vault we can allow developers to deploy an EIP-4337 (account abstraction) smart contract wallet managed by their console app with paymaster features. Developers should be able to interact with this SC wallet using the Galaxy API and Galaxy API Key.

From here the vault and assets will be a validated account for the user and many interactions should be doable without signing or gas fees.

Other features:

• The user should be able to exfiltrate the private key for any provisioned deposit vault to be used anywhere.
• Other apps should be able to ask for permission to read connected addresses and the user should be able to select which addresses they want to be known to the developer. This helps for collaborative and metaverse use cases.
• js sdk to allow user level signing of txns for deposit account?

How

TBD

Break out into vault milestone: https://github.com/proofzero/rollupid/milestones