fix: Memory leak fixes for IMAP client and webhooks worker

- Clear reconnectTimer in imap-client.js close() and delete() methods
  to prevent timer references keeping objects in memory after account removal

- Drain HTTP response body in webhooks.js on error responses to release
  connections back to undici connection pool

Author: andris9

lib/email-client/imap-client.js

@@ -1501,6 +1501,7 @@ class IMAPClient extends BaseClient {
         clearTimeout(this.untaggedExpungeTimer);
         clearTimeout(this.resyncTimer);
         clearTimeout(this.completedTimer);
+        clearTimeout(this.reconnectTimer);
 
         try {
             // Clean up all mailboxes
@@ -1544,6 +1545,7 @@ class IMAPClient extends BaseClient {
         clearTimeout(this.untaggedExpungeTimer);
         clearTimeout(this.resyncTimer);
         clearTimeout(this.completedTimer);
+        clearTimeout(this.reconnectTimer);
 
         this.isClosing = false;
         this.isClosed = true;

workers/webhooks.js

@@ -411,6 +411,12 @@ const notifyWorker = new Worker(
             }
 
             if (!res.ok) {
+                // Drain response body to release connection back to pool
+                try {
+                    await res.text();
+                } catch {
+                    // ignore drain errors
+                }
                 let err = new Error(res.statusText || `Invalid response: ${res.status} ${res.statusText}`);
                 err.statusCode = res.status;
                 throw err;