Scaffold loopback daemon client split

internal/app/session.go

@@ -46,6 +46,13 @@ type Session struct {
 	listenersMu sync.Mutex
 	listeners   atomic.Pointer[[]ChildEventListener]
 
+	// clientListeners is the network-client subscriber path. These
+	// listeners must be non-blocking and copy PTY chunks before enqueueing;
+	// daemon-internal observers (timers, debug capture, waiters) stay on
+	// listeners above so backpressure policy is isolated to clients.
+	clientListenersMu sync.Mutex
+	clientListeners   atomic.Pointer[[]ChildEventListener]
+
 	// persistStore records top-level command entries to a per-project
 	// JSON file so they can be re-spawned after patterm restarts.
 	// Optional; nil means "no persistence" (used by unit tests).
@@ -118,6 +125,16 @@ func (s *Session) Subscribe(l ChildEventListener) {
 	s.listeners.Store(&next)
 }
 
+func (s *Session) SubscribeClient(l ChildEventListener) {
+	s.clientListenersMu.Lock()
+	defer s.clientListenersMu.Unlock()
+	prev := s.clientListenersSnapshot()
+	next := make([]ChildEventListener, 0, len(prev)+1)
+	next = append(next, prev...)
+	next = append(next, l)
+	s.clientListeners.Store(&next)
+}
+
 // Unsubscribe removes a previously-registered listener. Safe to call
 // with a listener that wasn't registered (no-op).
 func (s *Session) Unsubscribe(l ChildEventListener) {
@@ -146,16 +163,30 @@ func (s *Session) listenersSnapshot() []ChildEventListener {
 	return *p
 }
 
+func (s *Session) clientListenersSnapshot() []ChildEventListener {
+	p := s.clientListeners.Load()
+	if p == nil {
+		return nil
+	}
+	return *p
+}
+
 func (s *Session) emitSpawn(c *Child) {
 	for _, l := range s.listenersSnapshot() {
 		l.OnChildSpawned(c)
 	}
+	for _, l := range s.clientListenersSnapshot() {
+		l.OnChildSpawned(c)
+	}
 }
 
 func (s *Session) emitExit(c *Child) {
 	for _, l := range s.listenersSnapshot() {
 		l.OnChildExited(c)
 	}
+	for _, l := range s.clientListenersSnapshot() {
+		l.OnChildExited(c)
+	}
 }
 
 // emitPTYOut dispatches a fresh PTY chunk to every listener. Listeners
@@ -165,18 +196,27 @@ func (s *Session) emitPTYOut(id string, chunk []byte) {
 	for _, l := range s.listenersSnapshot() {
 		l.OnPTYOut(id, chunk)
 	}
+	for _, l := range s.clientListenersSnapshot() {
+		l.OnPTYOut(id, chunk)
+	}
 }
 
 func (s *Session) emitStateChanged(id string, state IdleState) {
 	for _, l := range s.listenersSnapshot() {
 		l.OnChildStateChanged(id, state)
 	}
+	for _, l := range s.clientListenersSnapshot() {
+		l.OnChildStateChanged(id, state)
+	}
 }
 
 func (s *Session) emitClosed(id string) {
 	for _, l := range s.listenersSnapshot() {
 		l.OnChildClosed(id)
 	}
+	for _, l := range s.clientListenersSnapshot() {
+		l.OnChildClosed(id)
+	}
 }
 
 func (s *Session) ChildEnv() []string {