Idea - Optional state synchronization using decentralized file storage

# Overview
Consider a user who brings their private key/mnemonic from one device to another. If they use a snap, can the state be synchronized across these devices metamask extensions? This would be an interesting feature. A user could _opt-in_ to storing the state in IPFS and somehow linking it to their key so that they can access it when they move to different devices.

## More imagination
This would potentially set the stage for sharing state across snaps with different keys or building an application similar to NuCypher, where you can re-encrypt your state with someone elses key and maybe send it to them/their snap if it supports such a functionality.

No files, tests, entry points, or concrete acceptance criteria are named. Start by surveying the repository for existing snap state persistence and key-management entry points, then clarify the opt-in storage, device synchronization, and key-linking design before implementation; done cannot be determined from the issue alone.

Written by the indexing model from the issue text.