fix IMAPIdleHandler thread safety: pass idleTag via init, clean up event loop group on reconnect

Packages/MagnumOpusCore/Sources/IMAPClient/IMAPIdleClient.swift

@@ -67,6 +67,12 @@ public actor IMAPIdleClient {
 	// MARK: - Connection
 
 	private func connectAndLogin() async throws {
+		// Clean up previous connection if reconnecting
+		try? await channel?.close()
+		channel = nil
+		try? await group?.shutdownGracefully()
+		group = nil
+
 		let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
 		let sslContext = try NIOSSLContext(configuration: TLSConfiguration.makeClientConfiguration())
 		let hostname = host
@@ -138,16 +144,14 @@ public actor IMAPIdleClient {
 		// Iterative IDLE loop — avoids unbounded stack growth from recursion
 		while !Task.isCancelled {
 			// Swap response handler for IDLE handler
+			let idleTag = "IDLE1"
 			let (stream, streamContinuation) = AsyncStream<IMAPIdleEvent>.makeStream()
-			let idleHandler = IMAPIdleHandler(continuation: streamContinuation)
+			let idleHandler = IMAPIdleHandler(continuation: streamContinuation, idleTag: idleTag)
 
 			let oldHandler = try await getResponseHandler()
 			try await pipeline.removeHandler(oldHandler).get()
 			try await pipeline.addHandler(idleHandler).get()
 
-			let idleTag = "IDLE1"
-			idleHandler.setIdleTag(idleTag)
-
 			// Send IDLE command
 			let idleCommand = TaggedCommand(tag: idleTag, command: .idleStart)
 			channel.writeAndFlush(IMAPClientHandler.Message.part(.tagged(idleCommand)), promise: nil)