fix(analytics): Add permalink building to admin-ajax fallback

When JavaScript falls back to admin-ajax.php instead of the fast
search-endpoint.php, results were returned with empty permalinks.
This caused click tracking to log URLs in /?p=ID format.

Now both endpoints build proper permalinks using post_name:
- search-endpoint.php (fast): Already had the fix
- admin-ajax fallback: Added permalink building (lines 182-203)

Also flushed Redis cache to clear stale results.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

roi-apu-search.php

@@ -179,6 +179,29 @@ final class ROI_APU_Search_Plugin
             $offset = ($page - 1) * $per_page;
             $results = $search->run($term, $per_page, $offset, $category_ids);
 
+            // Build permalinks for each result (search engine returns empty permalink)
+            $site_url = rtrim(home_url(), '/');
+            $permalink_structure = get_option('permalink_structure', '/%postname%/');
+
+            foreach ($results['rows'] as &$row) {
+                if (empty($row['permalink'])) {
+                    $postName = $row['post_name'] ?? '';
+
+                    if (empty($postName)) {
+                        $row['permalink'] = $site_url . '/?p=' . $row['ID'];
+                        continue;
+                    }
+
+                    // Build according to permalink structure
+                    if (strpos($permalink_structure, '%post_id%') !== false) {
+                        $row['permalink'] = $site_url . '/' . $row['ID'] . '/';
+                    } else {
+                        $row['permalink'] = $site_url . '/' . $postName . '/';
+                    }
+                }
+            }
+            unset($row);
+
             // Log search for analytics
             $analytics_cfg = ROI_APU_Search_Analytics::get_config();
             $search_id = ROI_APU_Search_Analytics::logSearch(