dbus: add detached process management methods

New D-Bus methods on SessionManager:
- DetachProcess(sessionID) - detach currently running process
- ListDetached(sessionID) - list detached processes (pid/cmd/started/status)
- SignalDetached(sessionID, pid, signal) - send TERM or KILL
- GetDetachedOutput(sessionID, pid) - read ring buffer output
- DismissDetached(sessionID, pid) - remove exited process from list

New signal: ProcessDetached(sessionID) emitted on detach.

main.go

@@ -575,6 +575,87 @@ func (m *SessionManager) PeerSubmit(sessionID, peerID, prompt string) (bool, *db
 	return true, nil
 }
 
+// --- Detached Process Management ---
+
+func (m *SessionManager) DetachProcess(sessionID string) (bool, *dbus.Error) {
+	m.mu.Lock()
+	sess, ok := m.sessions[sessionID]
+	m.mu.Unlock()
+	if !ok {
+		return false, dbus.MakeFailedError(fmt.Errorf("session not found: %s", sessionID))
+	}
+	if !sess.core.Detach() {
+		return false, dbus.MakeFailedError(fmt.Errorf("no running process to detach"))
+	}
+	m.conn.Emit(busPath, busIface+".ProcessDetached", sessionID)
+	return true, nil
+}
+
+func (m *SessionManager) ListDetached(sessionID string) ([]string, *dbus.Error) {
+	m.mu.Lock()
+	sess, ok := m.sessions[sessionID]
+	m.mu.Unlock()
+	if !ok {
+		return nil, dbus.MakeFailedError(fmt.Errorf("session not found: %s", sessionID))
+	}
+	infos := sess.core.ListDetached()
+	out := make([]string, len(infos))
+	for i, info := range infos {
+		status := "running"
+		if info.Exited {
+			status = fmt.Sprintf("exited(%d)", info.ExitCode)
+		}
+		out[i] = fmt.Sprintf("%d\t%s\t%d\t%s", info.PID, info.Command, info.Started, status)
+	}
+	return out, nil
+}
+
+func (m *SessionManager) SignalDetached(sessionID string, pid int32, signal string) (bool, *dbus.Error) {
+	m.mu.Lock()
+	sess, ok := m.sessions[sessionID]
+	m.mu.Unlock()
+	if !ok {
+		return false, dbus.MakeFailedError(fmt.Errorf("session not found: %s", sessionID))
+	}
+	var sig int
+	switch strings.ToUpper(signal) {
+	case "TERM", "SIGTERM", "15":
+		sig = 15
+	case "KILL", "SIGKILL", "9":
+		sig = 9
+	default:
+		return false, dbus.MakeFailedError(fmt.Errorf("unsupported signal: %s (use TERM or KILL)", signal))
+	}
+	if err := sess.core.SignalDetached(int(pid), sig); err != nil {
+		return false, dbus.MakeFailedError(err)
+	}
+	return true, nil
+}
+
+func (m *SessionManager) GetDetachedOutput(sessionID string, pid int32) (string, *dbus.Error) {
+	m.mu.Lock()
+	sess, ok := m.sessions[sessionID]
+	m.mu.Unlock()
+	if !ok {
+		return "", dbus.MakeFailedError(fmt.Errorf("session not found: %s", sessionID))
+	}
+	output, err := sess.core.GetDetachedOutput(int(pid))
+	if err != nil {
+		return "", dbus.MakeFailedError(err)
+	}
+	return output, nil
+}
+
+func (m *SessionManager) DismissDetached(sessionID string, pid int32) (bool, *dbus.Error) {
+	m.mu.Lock()
+	sess, ok := m.sessions[sessionID]
+	m.mu.Unlock()
+	if !ok {
+		return false, dbus.MakeFailedError(fmt.Errorf("session not found: %s", sessionID))
+	}
+	return sess.core.DismissDetached(int(pid)), nil
+}
+
 // --- Notifications ---
 
 func (m *SessionManager) sendNotification(title, body string) {