feat: Implement complete ticket purchasing flow with new TicketsController

- Create new TicketsController with actions for name collection, creation, and checkout
- Add dedicated ticket views (new.html.erb, checkout.html.erb, show.html.erb)
- Update ticket_selection_controller.js to handle form submission via AJAX
- Add store_cart endpoint in EventsController for session-based cart management
- Update routes to support new ticket flow: /tickets/new, /create, /checkout
- Fix attribute name consistency across views (title→name, starts_at→start_time)
- Add Stripe checkout integration with proper error handling
- Remove deprecated collect_names flow in favor of streamlined approach

The flow is now: Event selection → AJAX cart storage → Name collection → Checkout → Payment

app/controllers/concerns/stripe_concern.rb

@@ -0,0 +1,18 @@
+module StripeConcern
+  extend ActiveSupport::Concern
+
+  # Check if Stripe is properly configured
+  def stripe_configured?
+    Rails.application.config.stripe[:secret_key].present?
+  end
+
+  # Stripe is now initialized at application startup, so this method is no longer needed
+  # but kept for backward compatibility
+  def initialize_stripe
+    return false unless stripe_configured?
+    
+    # Stripe is already initialized at application startup
+    Rails.logger.debug "Stripe already initialized at application startup"
+    true
+  end
+end