feat(prekey): add destroy() method for proper resource cleanup

Implements PreKeyManager.destroy() to prevent memory leaks during connection cleanup.

Changes:
- Added PreKeyManager.destroy() method that clears and pauses all PQueues
- Exposed destroy() in SignalKeyStoreWithTransaction type
- Integrated destroy() call in addTransactionCapability() to cleanup both PreKeyManager and keyQueues
- Added keys.destroy() call in socket.ts end() function alongside other cleanup operations

Benefits:
- Prevents memory leaks from orphaned PQueues
- Proper cleanup of PreKeyManager resources during disconnect
- Consistent with existing cleanup pattern (circuit breakers, session manager)
- Zero impact on active connections (only called during cleanup)

Observability:
- Added debug logs for tracking cleanup operations
- Logs include queue type and cleanup status

Cross-file analysis:
- PreKeyManager instantiated in auth-utils.ts:130
- addTransactionCapability() called in socket.ts:499
- cleanup happens in socket.ts:836 (end function)

https://claude.ai/code/session_33db9e93-e4c3-4859-9ff3-96d8864af1c4

src/Utils/auth-utils.ts

@@ -339,6 +339,25 @@ export const addTransactionCapability = (
 			} finally {
 				releaseTxMutexRef(key)
 			}
+		},
+
+		/**
+		 * Cleanup all resources (queues, managers)
+		 * Should be called during connection cleanup
+		 */
+		destroy: () => {
+			logger.debug('🗑️ Cleaning up transaction capability resources')
+			preKeyManager.destroy()
+
+			// Clear all key queues
+			keyQueues.forEach((queue, keyType) => {
+				queue.clear()
+				queue.pause()
+				logger.debug(`Queue for ${keyType} cleared and paused`)
+			})
+			keyQueues.clear()
+
+			logger.debug('Transaction capability cleanup completed')
 		}
 	}
 }

src/Utils/pre-key-manager.ts

@@ -123,4 +123,21 @@ export class PreKeyManager {
 			}
 		})
 	}
+
+	/**
+	 * Cleanup all queues and resources
+	 * Should be called during connection cleanup to prevent memory leaks
+	 */
+	destroy(): void {
+		this.logger.debug('🗑️ Destroying PreKeyManager')
+
+		this.queues.forEach((queue, keyType) => {
+			queue.clear()
+			queue.pause()
+			this.logger.debug(`Queue for ${keyType} cleared and paused`)
+		})
+
+		this.queues.clear()
+		this.logger.debug('PreKeyManager destroyed - all queues cleaned up')
+	}
 }