fix(mail): add periodic cleanup timers and proper shutdown handling for bounce manager and delivery queue; avoid mutating maps during iteration and prune stale rate-limiter stats to prevent memory growth

ts/mail/core/classes.bouncemanager.ts

@@ -88,7 +88,10 @@ export class BounceManager {
   
   // Store of bounced emails
   private bounceStore: BounceRecord[] = [];
-  
+
+  // Periodic cleanup timer for old bounce records
+  private cleanupInterval?: NodeJS.Timeout;
+
   // Cache of recently bounced email addresses to avoid sending to known bad addresses
   private bounceCache: LRUCache<string, {
     lastBounce: number;
@@ -135,6 +138,15 @@ export class BounceManager {
     this.loadSuppressionList().catch(error => {
       logger.log('error', `Failed to load suppression list on startup: ${error.message}`);
     });
+
+    // Start periodic cleanup of old bounce records (every 1 hour, removes records older than 7 days)
+    this.cleanupInterval = setInterval(() => {
+      const sevenDaysAgo = Date.now() - 7 * 24 * 60 * 60 * 1000;
+      const removed = this.clearOldBounceRecords(sevenDaysAgo);
+      if (removed > 0) {
+        logger.log('info', `Auto-cleanup removed ${removed} old bounce records`);
+      }
+    }, 60 * 60 * 1000);
   }
   
   /**
@@ -717,7 +729,7 @@ export class BounceManager {
    */
   public clearOldBounceRecords(olderThan: number): number {
     let removed = 0;
-    
+
     this.bounceStore = this.bounceStore.filter(bounce => {
       if (bounce.timestamp < olderThan) {
         removed++;
@@ -725,7 +737,17 @@ export class BounceManager {
       }
       return true;
     });
-    
+
     return removed;
   }
+
+  /**
+   * Stop the bounce manager and clear cleanup timers
+   */
+  public stop(): void {
+    if (this.cleanupInterval) {
+      clearInterval(this.cleanupInterval);
+      this.cleanupInterval = undefined;
+    }
+  }
 }