Post a webhook reply as an attachment only when the bot answered 200

A bot's reply becomes a message when the status is 200 and the type is text,
and an attachment otherwise, but the attachment branch never looked at the
status. Whenever a bot's endpoint failed, its error page landed in the room as
a file: a proxy's 502 page as attachment.html, a 404 as attachment.text.

Apply the text branch's 200 check to attachments too. The error reply test
answered without a content type, which skipped the attachment branch, so it
now answers with an HTML error page.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JVFo3Lt9T8M5NR7KxVvsZ2

app/models/webhook.rb

@@ -63,7 +63,7 @@ class Webhook < ApplicationRecord
     end
 
     def extract_attachment_from(response)
-      if response.content_type && mime_type = Mime::Type.lookup(response.content_type)
+      if response.code == "200" && response.content_type && mime_type = Mime::Type.lookup(response.content_type)
         ActiveStorage::Blob.create_and_upload! \
           io: StringIO.new(response.body), filename: "attachment.#{mime_type.symbol}", content_type: mime_type.to_s
       end

test/models/webhook_test.rb

@@ -41,7 +41,7 @@ class WebhookTest < ActiveSupport::TestCase
 
   test "delivery with error reply" do
     assert_no_difference -> { Message.count } do
-      WebMock.stub_request(:post, webhooks(:bender).url).to_return(status: 500, body: "Internal Error!", headers: {})
+      WebMock.stub_request(:post, webhooks(:bender).url).to_return(status: 500, body: "<h1>Internal Error!</h1>", headers: { "Content-Type" => "text/html" })
       response = webhooks(:bender).deliver(messages(:first))
     end
   end