Research about `did:plc` method adoption

[fforbeck]

Why?
What does it unlock?
How?

[fforbeck]

RFC

• rfc: DID:PLC integration for Storacha stack RFC#55

Code

• feat: did-plc package upload-service#273
• feat: resolve did:plc w3infra#477
• feat!: resolve multiple verifiers ucanto#381

This is not deployed as it depends on operations that create new did:plc documents, and update these documents. We already have this code in the Bsky app, and we would need a refactor to extract the relevant parts into a library - but it won't be covered in this research phase, and more details about that can be found in the RFC.