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

config/initializers/stripe.rb

@@ -1,4 +1,14 @@
 Rails.application.configure do
+  # Load environment variables from .env file if dotenv is not available
+  env_file = Rails.root.join('.env')
+  if File.exist?(env_file) && !defined?(Dotenv)
+    File.readlines(env_file).each do |line|
+      next if line.strip.empty? || line.start_with?('#')
+      key, value = line.split('=', 2)
+      ENV[key.strip] = value.strip if key && value
+    end
+  end
+
   # Try to get Stripe keys from environment variables first, then from credentials
   stripe_publishable_key = ENV["STRIPE_PUBLISHABLE_KEY"]
   stripe_secret_key = ENV["STRIPE_SECRET_KEY"]
@@ -19,7 +29,12 @@ Rails.application.configure do
     secret_key: stripe_secret_key,
     signing_secret: stripe_webhook_secret
   }
-end
 
-# Note: Stripe.api_key is NOT set here - it will be set during checkout process
-Rails.logger.info "Stripe configuration loaded - will initialize during checkout"
+  # Initialize Stripe API key at application startup if secret key is present
+  if stripe_secret_key.present?
+    Stripe.api_key = stripe_secret_key
+    Rails.logger.info "Stripe initialized at application startup"
+  else
+    Rails.logger.warn "Stripe secret key not found - Stripe will not be initialized"
+  end
+end