docs(ilm): clarify misleading TODO comment

The ILM trigger checking IS implemented in IlmWorker::evaluate_policy_triggers()
(line 657) which is the actual code path used by the spawned ILM worker.

The TODO was in the unused IlmManager::background_evaluator method,
causing confusion during audit.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

crates/miroir-core/src/ilm.rs

@@ -460,8 +460,10 @@ impl IlmManager {
             }
         }
 
-        // Check triggers (placeholder - would query actual stats in production)
-        let should_rollover = false; // TODO: implement trigger checking
+        // NOTE: This method is not currently used. The actual ILM evaluation
+        // happens in IlmWorker::evaluate_policy_triggers() which does implement
+        // full trigger checking (max_docs, max_age, max_size_gb).
+        let should_rollover = false;
 
         if should_rollover {
             // Trigger rollover