feat: improve campsites and events management UX

- Add map-based location picker with centered pin for campsites (two-step process)
- Hide edit buttons for campsites not owned by current user
- Allow numbers in campsite names (fix validateName function)
- Prepopulate edit form with existing campsite data
- Preserve country/province selection when confirming location
- Add real-time filter functionality to campsites table
- Fix events publish button error handling (use output buffering cleanup)
- Improve AJAX response handling with complete callback

Changes:
- src/pages/bookings/campsites.php: Location mode UI, filter, edit form improvements
- src/config/functions.php: Allow numbers in validateName regex
- src/admin/toggle_event_published.php: Clean output buffers before JSON response
- src/admin/admin_events.php: Use complete callback instead of success/error handlers

src/config/functions.php

@@ -2195,8 +2195,8 @@ function validateName($name, $minLength = 2, $maxLength = 100) {
         return false;
     }
     
-    // Only allow letters, spaces, hyphens, and apostrophes
-    if (!preg_match('/^[a-zA-Z\s\'-]+$/', $name)) {
+    // Allow letters, numbers, spaces, hyphens, and apostrophes
+    if (!preg_match('/^[a-zA-Z0-9\s\'-]+$/', $name)) {
         return false;
     }