feat: Add booking control during events

- Add allow_booking_during_event boolean field to events (defaults to false)
- Implement booking_allowed? method to check if tickets can be purchased
- Add event_started? and event_ended? helper methods
- Include new option in event edit form with clear explanation
- Display booking policy status on event show page
- Add visual indicator when booking is disabled during ongoing events
- Update controller to permit new parameter

This allows promoters to control whether attendees can purchase tickets
after an event has started, providing flexibility for different event types.

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

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

app/controllers/pages_controller.rb

@@ -71,23 +71,12 @@ class PagesController < ApplicationController
       @monthly_revenue = (0..5).map do |months_ago|
         start_date = months_ago.months.ago.beginning_of_month
         end_date = months_ago.months.ago.end_of_month
-<<<<<<< HEAD
-        
-        revenue = current_user.events
-                             .joins(:orders)
-                             .where(orders: { status: ['paid', 'completed'] })
-                             .where(orders: { created_at: start_date..end_date })
-                             .sum('orders.total_amount_cents') / 100.0
-        
-=======
-
         revenue = current_user.events
                              .joins(:orders)
                              .where(orders: { status: [ "paid", "completed" ] })
                              .where(orders: { created_at: start_date..end_date })
                              .sum("orders.total_amount_cents") / 100.0
 
->>>>>>> develop
         {
           month: start_date.strftime("%B %Y"),
           revenue: revenue