Implement access/claim in access-api

[alanshaw]

https://github.com/web3-storage/specs/blob/feat/w3-authorization/w3-access.md#accessclaim

Tasks

• define access/claim ability schema in @web3-storage/capabilities #408
• Implement access/delegate in access-api #393 - this is worth doing first as access/claim wont be useful for claiming anything until clients use access/delegate to write things that can be claimed comment
• I can access/claim as did:key:{} #455
• I can access/claim as did:mailto:{...} #454
  • unblocks "Access across multiple devices"

[gobengo]

See spec examples for how access/claim is claiming delegations written by access/delegate.

So I added #393 as a subtask of this to reflect that dependency

[gobengo]

Remember to try to include this optimization

• feat: handle access/delegate invocations without error #427 (comment)
• e.g. DelegationsStorage can have a method to query delegations out as car bytes but without parsing, that way we don't have to re-encode them to car bytes in the access/claim handler

[gobengo]

This is implemented in access-api main branch, and is depended on by @web3-storage/access as of #395