fix(tui): show an honest empty state when /plan opens before attach

internal/tui/plan.go

@@ -206,6 +206,11 @@ func (m *Model) planStripLabel() string {
 // syncPlanPanelMsg refreshes the tab's empty/unavailable copy from state.
 func (m *Model) syncPlanPanelMsg() {
 	switch {
+	case m.cl == nil || m.sessionID == "":
+		// No live session: fetchPlan is a silent no-op, so "loading plan…"
+		// would never resolve. Say why instead (attach completes → reset +
+		// refetch at the tail resolves this to a real snapshot).
+		m.panelMsg = "no active session yet — the plan loads when a run starts"
 	case m.planAvail == planUnavailable:
 		m.panelMsg = "plan unavailable on this engine · r retries"
 	case m.planAvail == planUnknown && !m.planInit:

internal/tui/plan_tab_test.go

@@ -74,6 +74,25 @@ func TestPlanTab_OpenerAndRenderedRows(t *testing.T) {
 	}
 }
 
+func TestPlanTab_UnattachedOpenerNeverShowsEternalLoading(t *testing.T) {
+	// Regression: opening the tab with no live session (no client / no
+	// session id) used to render "loading plan…" forever — fetchPlan was
+	// a silent no-op, so no reply ever resolved the placeholder.
+	m := newTestModel()
+	if c := m.openPlan(); c != nil {
+		t.Fatal("unattached opener must not issue a fetch")
+	}
+	if m.panel != panelPlan {
+		t.Fatalf("opener panel = %d", m.panel)
+	}
+	if strings.Contains(m.panelMsg, "loading") {
+		t.Fatalf("unattached tab shows eternal loading copy %q", m.panelMsg)
+	}
+	if got := plain(m.View()); !strings.Contains(got, "no active session") {
+		t.Errorf("unattached copy missing from view:\n%s", got)
+	}
+}
+
 func TestPlanTab_DetailFoldHouseGrammar(t *testing.T) {
 	m := newTestModel()
 	m.cl = &client.Client{}