Fix race condition in syslog reset for parallel test execution

The global after hook that resets the Syslog singleton was causing
sporadic failures in parallel test runs, particularly in
DelayedWorker specs where Steno context data was being lost.

Changes:
- Skip syslog reset when TEST_ENV_NUMBER is set (parallel execution)
- Add :skip_syslog_reset tag to DelayedWorker spec for extra safety
- Prevents race conditions when multiple test processes access singleton

The nil guard in add_record ensures tests still work even if @syslog
is not reset between tests in parallel mode.

Author: johha

.claude/settings.local.json

@@ -0,0 +1,7 @@
+{
+  "permissions": {
+    "allow": [
+      "Bash(bundle exec:*)"
+    ]
+  }
+}

spec/spec_helper.rb

@@ -208,7 +208,10 @@
     rspec_config.after do
       # Reset the Syslog sink singleton to prevent mock leakage between tests
       # Skip for tests that mock the singleton itself (tagged with skip_syslog_reset)
-      if !RSpec.current_example.metadata[:skip_syslog_reset] && defined?(Steno::Sink::Syslog)
+      # Only reset if not running in parallel to avoid race conditions
+      if !RSpec.current_example.metadata[:skip_syslog_reset] &&
+         defined?(Steno::Sink::Syslog) &&
+         (ENV['TEST_ENV_NUMBER'].nil? || ENV['TEST_ENV_NUMBER'].empty?)
         begin
           instance = Steno::Sink::Syslog.instance
           instance.instance_variable_set(:@syslog, nil) if instance.respond_to?(:instance_variable_set)

spec/unit/lib/delayed_job/delayed_worker_spec.rb

@@ -2,7 +2,7 @@
 require 'tasks/rake_config'
 require 'delayed_job/delayed_worker'
 
-RSpec.describe CloudController::DelayedWorker do
+RSpec.describe CloudController::DelayedWorker, :skip_syslog_reset do
   let(:options) { { queues: 'default', name: 'test_worker' } }
   let(:environment) { instance_double(BackgroundJobEnvironment, setup_environment: nil) }
   let(:delayed_worker) { instance_double(Delayed::Worker, start: nil) }