feat (recovery): Introduced panic recovery and monitoring mechanisms.

A new recovery package has been added, containing Recoverer and PanicMetrics, for capturing panics in goroutines.
It records stack trace information and provides statistical metrics. This mechanism is also integrated into the TCP connector and listener.
Enhance service stability and observability.

internal/server/tcp/listener.go

@@ -11,6 +11,7 @@ import (
 
 	"drip/internal/server/tunnel"
 	"drip/internal/shared/pool"
+	"drip/internal/shared/recovery"
 	"go.uber.org/zap"
 )
 
@@ -32,6 +33,8 @@ type Listener struct {
 	connections   map[string]*Connection
 	connMu        sync.RWMutex
 	workerPool    *pool.WorkerPool // Worker pool for connection handling
+	recoverer     *recovery.Recoverer
+	panicMetrics  *recovery.PanicMetrics
 }
 
 func NewListener(address string, tlsConfig *tls.Config, authToken string, manager *tunnel.Manager, logger *zap.Logger, portAlloc *PortAllocator, domain string, publicPort int, httpHandler http.Handler, responseChans HTTPResponseHandler) *Listener {
@@ -46,6 +49,9 @@ func NewListener(address string, tlsConfig *tls.Config, authToken string, manage
 		zap.Int("queue_size", queueSize),
 	)
 
+	panicMetrics := recovery.NewPanicMetrics(logger, nil)
+	recoverer := recovery.NewRecoverer(logger, panicMetrics)
+
 	return &Listener{
 		address:       address,
 		tlsConfig:     tlsConfig,
@@ -60,6 +66,8 @@ func NewListener(address string, tlsConfig *tls.Config, authToken string, manage
 		stopCh:        make(chan struct{}),
 		connections:   make(map[string]*Connection),
 		workerPool:    workerPool,
+		recoverer:     recoverer,
+		panicMetrics:  panicMetrics,
 	}
 }
 
@@ -86,6 +94,7 @@ func (l *Listener) Start() error {
 // acceptLoop accepts incoming connections
 func (l *Listener) acceptLoop() {
 	defer l.wg.Done()
+	defer l.recoverer.Recover("acceptLoop")
 
 	for {
 		select {
@@ -114,12 +123,20 @@ func (l *Listener) acceptLoop() {
 		}
 
 		l.wg.Add(1)
-		submitted := l.workerPool.Submit(func() {
-			l.handleConnection(conn)
-		})
+		submitted := l.workerPool.Submit(l.recoverer.WrapGoroutine(
+			fmt.Sprintf("handleConnection-%s", conn.RemoteAddr().String()),
+			func() {
+				l.handleConnection(conn)
+			},
+		))
 
 		if !submitted {
-			go l.handleConnection(conn)
+			l.recoverer.SafeGo(
+				fmt.Sprintf("handleConnection-fallback-%s", conn.RemoteAddr().String()),
+				func() {
+					l.handleConnection(conn)
+				},
+			)
 		}
 	}
 }
@@ -128,6 +145,12 @@ func (l *Listener) acceptLoop() {
 func (l *Listener) handleConnection(netConn net.Conn) {
 	defer l.wg.Done()
 	defer netConn.Close()
+	defer l.recoverer.RecoverWithCallback("handleConnection", func(p interface{}) {
+		connID := netConn.RemoteAddr().String()
+		l.connMu.Lock()
+		delete(l.connections, connID)
+		l.connMu.Unlock()
+	})
 
 	tlsConn, ok := netConn.(*tls.Conn)
 	if !ok {