Add Docker deployment files for Unity infrastructure migration

config/puma_docker.rb

@@ -0,0 +1,17 @@
+# Puma configuration for Docker deployment
+application_path = File.expand_path('..', __dir__)
+directory application_path
+
+environment ENV.fetch('RAILS_ENV') { 'production' }
+pidfile "#{application_path}/tmp/puma/pid"
+state_path "#{application_path}/tmp/puma/state"
+
+# Log to stdout/stderr in Docker
+stdout_redirect '/dev/stdout', '/dev/stderr', true
+
+# Use PORT env var (default 3000 for Coolify)
+port ENV.fetch('PORT') { 3000 }
+
+workers ENV.fetch('WEB_CONCURRENCY') { 3 }
+preload_app!
+threads 5, 16