improve: add clarifying comments to database index update process

Added comments to clarify the two-step process of removing old tokens
and bulk inserting new ones. While this is two queries, it's still
efficient as the insert is done in bulk rather than individual inserts.

Author: ginkelsoft-development

src/Traits/HasEncryptedSearchIndex.php

@@ -125,10 +125,12 @@ public function updateSearchIndex(): void
         if ($useElastic) {
             $this->syncToElasticsearch($rows);
         } else {
+            // Remove existing tokens for this model before inserting new ones
             SearchIndex::where('model_type', static::class)
                 ->where('model_id', $this->getKey())
                 ->delete();
 
+            // Bulk insert all new tokens in a single query
             SearchIndex::insert($rows);
         }
     }