Config for separate primary domain Nostr pubkey

Allow to configure a separate key for the NIP-05 address of the primary
domain vs the accounts domain.

app/controllers/well_known_controller.rb

@@ -10,8 +10,14 @@ class WellKnownController < ApplicationController
     relay_url = Setting.nostr_relay_url.presence
 
     if params[:name] == "_"
-      # pubkey for the primary domain without a username (e.g. kosmos.org)
-      res = { names: { "_": Setting.nostr_public_key } }
+      if domain == Setting.primary_domain
+        # pubkey for the primary domain without a username (e.g. kosmos.org)
+        res = { names: { "_": Setting.nostr_public_key_primary_domain || Setting.nostr_public_key } }
+      else
+        # pubkey for the akkounts domain without a username (e.g. accounts.kosmos.org)
+        res = { names: { "_": Setting.nostr_public_key } }
+      end
+
       res[:relays] = { "_" => [ relay_url ] } if relay_url
     else
       @user = User.where(cn: params[:name], ou: domain).first