Improve nostr settings, fix allowsNostr property name

app/controllers/lnurlpay_controller.rb

@@ -18,8 +18,8 @@ class LnurlpayController < ApplicationController
       commentAllowed: MAX_COMMENT_CHARS
     }
 
-    if Setting.nostr_enabled? && Setting.nostr_private_key.present?
-      res[:allows_nostr] = true
+    if Setting.nostr_enabled?
+      res[:allowsNostr] = true
       res[:nostrPubkey] = Setting.nostr_public_key
     end
 
@@ -52,7 +52,7 @@ class LnurlpayController < ApplicationController
       return
     end
 
-    if params[:nostr].present?# TODO && Setting.nostr_enabled?
+    if params[:nostr].present? && Setting.nostr_enabled?
       handle_zap_request amount, params[:nostr], params[:lnurl]
     else
       handle_pay_request address, amount, comment

app/models/setting.rb

@@ -160,7 +160,8 @@ class Setting < RailsSettings::Base
   # Nostr
   #
 
-  field :nostr_enabled, type: :boolean, default: false
+  field :nostr_enabled, type: :boolean,
+    default: ENV["NOSTR_PRIVATE_KEY"].present?
 
   field :nostr_private_key, type: :string,
     default: ENV["NOSTR_PRIVATE_KEY"].presence