Replace old plugin headers with proper file docblocks, add ABSPATH guards

- open-graph-tags.php: replace Plugin Name header with package docblock
- featured-image-generator.php: same cleanup
- sp-event-permalink.php: same cleanup, normalize indentation to tabs,
  collapse redundant switch cases (league/tournament both map to 'game')

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

includes/featured-image-generator.php

@@ -1,10 +1,15 @@
 <?php
-/*
-Plugin Name: SP Event Image Generator
-Description: Auto-generates featured images for SP Events by combining team colors and logos.
-Version: 1.0
-Author: Your Name
-*/
+/**
+ * SP Event featured-image generator.
+ *
+ * Auto-generates bisected team-color images for SP Events.
+ *
+ * @package Tonys_Sportspress_Enhancements
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
 
 function generate_bisected_image($color1, $color2, $logo1_path, $logo2_path) {
     $width = 1200;