fix(backend): Eliminate N+1 queries for reaction_added events

src/Model/Table/MessagesTable.php

@@ -91,6 +91,10 @@ public function validationDefault(Validator $validator): Validator
      * Returns a rules checker object that will be used for validating
      * application integrity.
      *
+     * Note: existsIn validation rules are defined here but may be skipped during save
+     * when called with pre-loaded User entities (e.g., in AwardService). Database
+     * foreign key constraints provide backup enforcement in such cases.
+     *
      * @param \Cake\ORM\RulesChecker $rules The rules object to be modified.
      * @return \Cake\ORM\RulesChecker
      */

src/Service/AwardService.php

@@ -61,7 +61,9 @@ private function gibToUser(
                 'type' => true,
             ],
         ]);
-        $messagesTable->saveOrFail($message);
+        // Skip ORM validation since User entities are already loaded and guaranteed to exist.
+        // Database foreign key constraints will enforce referential integrity.
+        $messagesTable->saveOrFail($message, ['validate' => false]);
 
         $span = SentrySdk::getCurrentHub()->getSpan();
         if ($span !== null) {