feat(nostr): nostr-based account registration and verification

Rebuilt the nostr registration feature cleanly on top of current ergo
mainline (origin/master), dropping the stale ergo reversions that were
entangled in the original squashed branch.

- New irc/nostr package: NIP-04/NIP-17 DMs, NIP-05 resolution, relay
  connect/auth, and identifier helpers.
- Registration/verification via nostr: parseCallback auto-detects nostr
  identifiers (NIP-05, npub, hex pubkey) and dispatches a verification DM.
- Nostr-based cloaked hostnames for accounts (opt-in via
  ip-cloaking.nostr-hostnames), applied at the account-cloak sites.
- Config: accounts.registration.nostr-verification and the
  nostr-hostnames cloak option, with matching default.yaml and help text.
- Adds github.com/nbd-wtf/go-nostr and vendored dependencies.

vendor/github.com/coder/websocket/doc.go

@@ -0,0 +1,34 @@
+//go:build !js
+// +build !js
+
+// Package websocket implements the RFC 6455 WebSocket protocol.
+//
+// https://tools.ietf.org/html/rfc6455
+//
+// Use Dial to dial a WebSocket server.
+//
+// Use Accept to accept a WebSocket client.
+//
+// Conn represents the resulting WebSocket connection.
+//
+// The examples are the best way to understand how to correctly use the library.
+//
+// The wsjson subpackage contain helpers for JSON and protobuf messages.
+//
+// More documentation at https://github.com/coder/websocket.
+//
+// # Wasm
+//
+// The client side supports compiling to Wasm.
+// It wraps the WebSocket browser API.
+//
+// See https://developer.mozilla.org/en-US/docs/Web/API/WebSocket
+//
+// Some important caveats to be aware of:
+//
+//   - Accept always errors out
+//   - Conn.Ping is no-op
+//   - Conn.CloseNow is Close(StatusGoingAway, "")
+//   - HTTPClient, HTTPHeader and CompressionMode in DialOptions are no-op
+//   - *http.Response from Dial is &http.Response{} with a 101 status code on success
+package websocket // import "github.com/coder/websocket"