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/admin/toggle_event_published.php

@@ -1,9 +1,21 @@
 <?php
+// Set JSON header FIRST before any includes that might output
+header('Content-Type: application/json');
+header('Cache-Control: no-cache, no-store, must-revalidate');
+header('Pragma: no-cache');
+header('Expires: 0');
+
+// Clean any output buffers before including header
+while (ob_get_level() > 0) {
+    ob_end_clean();
+}
+
 $rootPath = dirname(dirname(__DIR__));
 include_once($rootPath . '/header.php');
 checkAdmin();
 
-header('Content-Type: application/json');
+// Clean output buffer again in case header.php added content
+ob_clean();
 
 $event_id = $_POST['event_id'] ?? null;
 
@@ -44,6 +56,7 @@ try {
     $update_stmt->bind_param("ii", $new_status, $event_id);
 
     if ($update_stmt->execute()) {
+        ob_clean(); // Clean any buffered output before sending JSON
         http_response_code(200);
         echo json_encode([
             'status' => 'success',
@@ -55,6 +68,7 @@ try {
     }
     $update_stmt->close();
 } catch (Exception $e) {
+    ob_clean(); // Clean any buffered output before sending JSON
     http_response_code(500);
     echo json_encode(['status' => 'error', 'message' => 'Database error: ' . $e->getMessage()]);
 }