session: store remote target, expose in cfg read

The remote= field is now visible when reading s/{id}/cfg,
and stored on the Session struct for future persistence.

session/session.go

@@ -38,6 +38,7 @@ type Session struct {
 	plan       []byte
 	prevPrompt []byte // last submitted prompt; overwritten on each new submission
 	peers      map[string]bool // peer session IDs (bidirectional links)
+	remote     string // SSH target for remote execution (empty = local)
 
 	// Cached model list (expensive API call; refreshed every 24h).
 	modelsMu      sync.Mutex
@@ -1043,6 +1044,7 @@ func (s *Manager) CreateSession(args []string) (string, error) {
 	ctx, cancel := context.WithCancel(context.Background())
 	sess := NewSession(sessID, core, ctx, cancel)
 	sessPtr = sess
+	sess.remote = remoteTarget
 
 	s.mu.Lock()
 	sess.uname = uname

session/sessionfile.go

@@ -272,6 +272,7 @@ func (h *sessionHelper) cfgContent() string {
 	fmt.Fprintf(&sb, "model=%s\n", h.sess.Core.ModelName())
 	fmt.Fprintf(&sb, "agent=%s\n", h.sess.Core.AgentName())
 	fmt.Fprintf(&sb, "cwd=%s\n", h.sess.Core.CWD())
+	fmt.Fprintf(&sb, "remote=%s\n", h.sess.remote)
 	fmt.Fprintf(&sb, "maxTokens=%d\n", p.MaxTokens)
 	fmt.Fprintf(&sb, "maxCompletionTokens=%d\n", p.MaxCompletionTokens)
 	if p.Temperature != nil {