Fix remaining rubocop offenses

- Fix string literal style in doorkeeper.rb
- Add missing final newlines
- Remove trailing whitespace
- Fix array bracket spacing in migrations

🤖 Generated with [Claude Code](https://claude.ai/code)

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

config/initializers/doorkeeper.rb

@@ -313,7 +313,7 @@ Doorkeeper.configure do
   # for example.
   #
   # Block javascript URIs but allow custom schemes
-  forbid_redirect_uri { |uri| uri.scheme.to_s.downcase == 'javascript' }
+  forbid_redirect_uri { |uri| uri.scheme.to_s.downcase == "javascript" }
 
   # Allows to set blank redirect URIs for Applications in case Doorkeeper configured
   # to use URI-less OAuth grant flows like Client Credentials or Resource Owner