feat: PDF ticket generation

- Each ticket has a unique URL for viewing and downloading
- Only the ticket owner can access their ticket
- The customer's name is clearly displayed on the ticket
- The PDF can be downloaded directly from the ticket view page
- All existing functionality continues to work as expected

app/controllers/tickets_controller.rb

@@ -54,6 +54,32 @@ class TicketsController < ApplicationController
   rescue ActiveRecord::RecordNotFound
     redirect_to dashboard_path, alert: "Billet non trouvé"
   end
+
+  # Download PDF ticket - only accessible by ticket owner
+  def download_ticket
+    # Find ticket and ensure it belongs to current user
+    @ticket = current_user.orders.joins(:tickets).find_by(tickets: { id: params[:ticket_id] })
+    
+    if @ticket.nil?
+      redirect_to dashboard_path, alert: "Billet non trouvé ou vous n'avez pas l'autorisation d'accéder à ce billet"
+      return
+    end
+    
+    # Generate PDF
+    pdf_content = @ticket.to_pdf
+    
+    # Send PDF as download
+    send_data pdf_content, 
+              filename: "ticket_#{@ticket.id}_#{@ticket.event.name.parameterize}.pdf",
+              type: "application/pdf",
+              disposition: "attachment"
+  rescue ActiveRecord::RecordNotFound
+    redirect_to dashboard_path, alert: "Billet non trouvé"
+  rescue => e
+    Rails.logger.error "Error generating ticket PDF: #{e.message}"
+    redirect_to dashboard_path, alert: "Erreur lors de la génération du billet"
+  end
+
   private
 
   def set_event