fix: UsageMatcher reads Divi 4 shortcodes like WordPress and Divi, everywhere (ruling P24)

- G1: every decoded string value of a Divi 5 opener is scanned for shortcodes;
  outside the openers only the remaining content is.
- G2: attributes are parsed like shortcode_parse_atts() and global_module is
  cast with (int), as Divi does.
- G3: a non-empty global_module other than "0" that casts to 0 makes Divi
  render the newest layout, so it counts for every entry (fail closed).
- The prefilter LIKEs use LOWER(post_content), so they are case-insensitive
  under any collation.
- The guide describes the fail-closed rule without an absolute claim.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/Integrations/Divi/Library/GlobalUsages.php

@@ -127,7 +127,7 @@ class GlobalUsages
     /**
      * Every post (no revision, not trashed) that shows $libraryId (ruling P23, fail closed). The
      * candidates come from one query (ID, status and type only): content with "globalModule", a
-     * Divi 4 "global_module" or a JSON escape of a letter (an escaped key such as globalModule
+     * Divi 4 "global_module" (both case-insensitive) or a JSON escape of a letter (an escaped key such as globalModule
      * always has one). Their content is then read in chunks of CONTENT_CHUNK and parsed by
      * UsageMatcher; beyond PARSE_CAP candidates the rest counts as references unread (audit L1).
      *
@@ -158,10 +158,11 @@ class GlobalUsages
         // phpcs:disable WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.DirectDatabaseQuery
         $rows = $db->get_results(
             $db->prepare(
-                'SELECT ID, post_status, post_type FROM ' . $db->posts . ' WHERE (post_content LIKE %s OR '
-                    . "post_content LIKE %s OR post_content REGEXP %s) AND post_type <> 'revision' AND "
+                // Ruling P24: LOWER() keeps the LIKEs case-insensitive under any column collation.
+                'SELECT ID, post_status, post_type FROM ' . $db->posts . ' WHERE (LOWER(post_content) LIKE %s OR '
+                    . "LOWER(post_content) LIKE %s OR post_content REGEXP %s) AND post_type <> 'revision' AND "
                     . self::LISTED . ' ORDER BY ID ASC',
-                '%' . $db->esc_like('globalModule') . '%',
+                '%' . $db->esc_like('globalmodule') . '%',
                 '%' . $db->esc_like('global_module') . '%',
                 $escapedLetter
             ),