fix: lit/library-list search by title, own entries for authors, cursor without hidden rows (L3)

search uses search_columns post_title; users without edit_others_posts on
et_pb_layout query their own entries only (PostGuard::ownPostsOnly); the
cursor counts the entries shown, never the rows left out.

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

src/Integrations/Divi/Library/DiviLibraryStore.php

@@ -70,8 +70,9 @@ class DiviLibraryStore
     /**
      * Published entries, $limit + 1 of them (Cursor::page() tells whether there are more).
      *
-     * @param array{layout_type?: string, scope?: string, search?: string, category?: string} $filters
-     *        scope: "global" or "normal"; category: name of a layout_category term.
+     * @param array{layout_type?: string, scope?: string, search?: string, category?: string, author?: int} $filters
+     *        scope: "global" or "normal"; search: in the title; category: name of a layout_category
+     *        term; author: only this user's entries.
      * @return list<WP_Post>
      */
     public function find(array $filters, int $limit, int $offset): array
@@ -101,6 +102,12 @@ class DiviLibraryStore
         ];
         if (($filters['search'] ?? '') !== '') {
             $args['s'] = $filters['search'];
+            // Audit L3: the title only – content is block JSON, and entries the user may not read
+            // must not be findable by their content.
+            $args['search_columns'] = ['post_title'];
+        }
+        if (is_int($filters['author'] ?? null)) {
+            $args['author'] = $filters['author'];
         }
         if ($taxQuery !== []) {
             // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_tax_query -- the library is small.