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

.env.example

@@ -39,9 +39,11 @@ SMTP_ENABLE_STARTTLS=false
 # SMTP_STARTTLS=true
 
 # Application variables
-STRIPE_API_KEY=1337
+STRIPE_PUBLISHABLE_KEY=pk_test_51S1M7BJWx6G2LLIXYpTvi0hxMpZ4tZSxkmr2Wbp1dQ73MKNp4Tyu4xFJBqLXK5nn4E0nEf2tdgJqEwWZLosO3QGn00kMvjXWGW
+STRIPE_SECRET_KEY=sk_test_51S1M7BJWx6G2LLIXK2pdLpRKb9Mgd3sZ30N4ueVjHepgxQKbWgMVJoa4v4ESzHQ6u6zJjO4jUvgLYPU1QLyAiFTN00sGz2ortW
+STRIPE_WEBHOOK_SECRET=LaReunion974
 
-# OpenAI login
+# Scaleway login
 OPENAI_API_KEY=f66dbb5f-9770-4f81-b2ea-eb7370bc9aa5
 OPENAI_BASE_URL=https://api.scaleway.ai/v1
 OPENAI_MODEL=devstral-small-2505