fix: Resolve tickets controller Event lookup issues

- Fix Event attribute name from starts_at to start_time in orders/new view
- Update TicketsController#set_event to use session[:event_id] as fallback when params[:id] is not available
- Remove duplicate Event.find call in tickets#create action
- Fix form submission path in tickets/new to use parameterless route
- Add debug logging to troubleshoot event ID resolution
- Update redirect paths to use proper route helpers

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

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

app/controllers/tickets_controller.rb

@@ -46,11 +46,9 @@ class TicketsController < ApplicationController
     @cart_data = session[:pending_cart] || {}
 
     if @cart_data.empty?
-      redirect_to event_path(params[:slug], params[:id]), alert: "Aucun billet sélectionné"
+      redirect_to event_path(@event.slug, @event), alert: "Aucun billet sélectionné"
       return
     end
-
-    @event = Event.includes(:ticket_types).find(params[:id])
     success = false
     
     ActiveRecord::Base.transaction do
@@ -89,12 +87,12 @@ class TicketsController < ApplicationController
       session.delete(:pending_cart)
       redirect_to checkout_order_path(@order)
     else
-      redirect_to ticket_new_path(@event.slug, @event.id)
+      redirect_to ticket_new_path
     end
   rescue => e
     error_message = e.message.present? ? e.message : "Erreur inconnue"
     flash[:alert] = "Une erreur est survenue: #{error_message}"
-    redirect_to ticket_new_path(params[:slug], params[:id])
+    redirect_to ticket_new_path
   end
 
   # Redirect to order-based checkout
@@ -147,7 +145,21 @@ class TicketsController < ApplicationController
   private
 
   def set_event
-    @event = Event.includes(:ticket_types).find(params[:id])
+    event_id = params[:id] || session[:event_id]
+    
+    Rails.logger.debug "TicketsController#set_event - params[:id]: #{params[:id].inspect}, session[:event_id]: #{session[:event_id].inspect}"
+    
+    unless event_id
+      Rails.logger.error "TicketsController#set_event - No event ID found"
+      redirect_to events_path, alert: "Aucun événement spécifié"
+      return
+    end
+    
+    @event = Event.includes(:ticket_types).find(event_id)
+    Rails.logger.debug "TicketsController#set_event - Found event: #{@event.id} - #{@event.name}"
+  rescue ActiveRecord::RecordNotFound
+    Rails.logger.error "TicketsController#set_event - Event not found with ID: #{event_id}"
+    redirect_to events_path, alert: "Événement non trouvé"
   end
 
   def ticket_params