Fix CI lint failures in SMS provider work

Rubocop:
- lib/sms/providers/{signalwire,twilio}.rb: collapse the
  Net::HTTPSuccess success-path `if` into modifier form
  (Style/IfUnlessModifier).
- lib/sms/providers/signalwire.rb: `delete_suffix('/')` instead of
  `sub(%r{/\z}, '')` (Performance/DeleteSuffix).
- app/controllers/sms_settings_controller.rb: move SECRET_KEYS to
  the top of the class so it isn't sandwiched under `private`
  (Lint/UselessConstantScoping). Ruby constants aren't actually
  privatised by a preceding `private` keyword anyway.

Erblint:
- app/views/sms_settings/index.html.erb: replace `javascript_tag do`
  with a raw `<script nonce=...>` block so erblint's
  AvoidUsingJavascriptTag rule is satisfied. CSP nonce comes from
  Rails' content_security_policy_nonce helper, same source as before.
- Inline the ERB block-opener so Ruby doesn't see a leading empty
  line (Layout/LeadingEmptyLines).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/controllers/sms_settings_controller.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class SmsSettingsController < ApplicationController
+  SECRET_KEYS = %w[basic_auth_token twilio_auth_token voipms_api_password signalwire_api_token].freeze
+
   before_action :load_encrypted_config
   authorize_resource :encrypted_config, only: :index
   authorize_resource :encrypted_config, parent: false, only: %i[create test_message]
@@ -46,8 +48,6 @@ class SmsSettingsController < ApplicationController
                                             key: EncryptedConfig::SMS_CONFIGS_KEY)
   end
 
-  SECRET_KEYS = %w[basic_auth_token twilio_auth_token voipms_api_password signalwire_api_token].freeze
-
   def build_sms_value
     submitted = params.require(:encrypted_config).permit(value: {})[:value].to_h
     existing = @encrypted_config.value || {}

app/views/sms_settings/index.html.erb

@@ -5,8 +5,7 @@
 
     <% value = @encrypted_config.value || {} %>
     <% sms_live = Sms.enabled_for?(current_account) %>
-    <%
-      provider_labels = {
+    <% provider_labels = {
         'bulkvs' => 'BulkVS',
         'twilio' => 'Twilio',
         'voipms' => 'VoIP.ms',
@@ -185,7 +184,7 @@
   <div class="w-0 md:w-52"></div>
 </div>
 
-<%= javascript_tag nonce: true do %>
+<script nonce="<%= content_security_policy_nonce %>">
   (function () {
     const select = document.getElementById('sms_provider_select')
     if (!select) return
@@ -199,4 +198,4 @@
     select.addEventListener('change', sync)
     sync()
   })()
-<% end %>
+</script>

lib/sms/providers/signalwire.rb

@@ -41,7 +41,7 @@ module Sms
       private
 
       def normalize_space_url(raw)
-        raw.to_s.strip.sub(%r{\Ahttps?://}, '').sub(%r{/\z}, '')
+        raw.to_s.strip.sub(%r{\Ahttps?://}, '').delete_suffix('/')
       end
 
       def format_e164(raw)
@@ -70,9 +70,7 @@ module Sms
           { 'raw' => response.body.to_s }
         end
 
-        if response.is_a?(Net::HTTPSuccess) && body['error_code'].nil?
-          return body
-        end
+        return body if response.is_a?(Net::HTTPSuccess) && body['error_code'].nil?
 
         code = body['code'] || body['error_code']
         message = body['message'] || body['error_message'] || body['raw'] || "HTTP #{response.code}"

lib/sms/providers/twilio.rb

@@ -70,9 +70,7 @@ module Sms
           { 'raw' => response.body.to_s }
         end
 
-        if response.is_a?(Net::HTTPSuccess) && body['error_code'].nil?
-          return body
-        end
+        return body if response.is_a?(Net::HTTPSuccess) && body['error_code'].nil?
 
         code = body['code'] || body['error_code']
         message = body['message'] || body['error_message'] || body['raw'] || "HTTP #{response.code}"