Remove additional Conductor-specific files per code review

- Removed CONDUCTOR_SETUP.md (separate PR)
- Reverted .gitignore to remove rails_helper.local.rb entry (separate PR)

These Conductor workspace setup files will be in a separate PR.

Author: justin808

.gitignore

@@ -80,6 +80,3 @@ ssr-generated
 # Playwright test artifacts (from cypress-on-rails gem)
 /spec/dummy/e2e/playwright-report/
 /spec/dummy/test-results/
-
-# Local test configuration (Conductor workspaces, etc.)
-/spec/dummy/spec/rails_helper.local.rb