0.0.3 — multi-resolver fallback #3

0.0.1 hardcodes https://solid.social as the resolver host. Users registered with a different JSS server (or any other did:nostr-aware server) get a 404 + the "your key isn't linked to a pod at solid.social" coaching message.

The next step short of full relay-based resolution (#414 territory, tracked as 0.0.4 here) is to try a list of resolvers in order, falling back if any one 404s.

Suggested resolver order

1. The configured ?resolver=... URL param (explicit user choice)
2. The host stored from a previous successful resolution (see 0.0.5)
3. https://solid.social
4. https://nostr.social (uses the same .well-known/did/nostr/* shape per the did:nostr spec)
5. https://nostr.rocks (same)

Acceptance

• Resolver list configurable via repeated ?resolver=... URL params (or a comma-separated single param)
• First non-404 response wins; the checklist (0.0.2) shows which resolver succeeded
• All-404 case displays the same "your key isn't linked" coaching, plus the list of resolvers tried

Refs

• 0.0.4 (JSS#414) — relays as the long-term decentralization step