#19282: feat(nostr): Update Nostr Channel to Support Rendering, Thinking, Tools Calls, etc. [NIP-63]

## Summary This PR migrates the Nostr channel to [NIP-63](https://github.com/nostr-protocol/nips/pull/2226) messaging and updates the Admin UI onboarding/setup flow accordingly. ## Changes - Switch Nostr transport path to NIP-63-only behavior - Add/refresh onboarding adapter and UI flow for Nostr channel setup - Update channel docs and extension docs/changelog - Add startup + onboarding + UI tests - Add/adjust live-check and debug tooling for Nostr protocol behavior