test(tui): cover medium sidebar footer hint

internal/tui/model.go

@@ -3036,9 +3036,18 @@ func (m model) composerIdleHint() string {
 	case tierNarrow:
 		hint = "? shortcuts"
 	case tierMedium:
-		hint = fmt.Sprintf("? shortcuts · Ctrl+X cmds · %s sidebar", sidebarKey)
+		parts := []string{"? shortcuts", "Ctrl+X cmds"}
+		if m.sidebarAvailable() {
+			parts = append(parts, sidebarKey+" sidebar")
+		}
+		hint = strings.Join(parts, " · ")
 	default:
-		hint = fmt.Sprintf("? shortcuts · Ctrl+X cmds · %s sidebar · %s detail · %s copy · Shift+Tab mode", sidebarKey, detailKey, mouseKey)
+		parts := []string{"? shortcuts", "Ctrl+X cmds"}
+		if m.sidebarAvailable() {
+			parts = append(parts, sidebarKey+" sidebar")
+		}
+		parts = append(parts, detailKey+" detail", mouseKey+" copy", "Shift+Tab mode")
+		hint = strings.Join(parts, " · ")
 	}
 	return zeroTheme.faint.Render(hint)
 }

internal/tui/model_test.go

@@ -2501,9 +2501,36 @@ func TestComposerIdleHintAndJumpCue(t *testing.T) {
 	m.width, m.height = 100, 30
 	m.transcript = append(m.transcript, transcriptRow{kind: rowAssistant, text: "hi", final: true})
 
-	// Idle, empty composer, managed mode -> the discoverability hint shows.
-	if h := plainRender(t, m.composerIdleHint()); !strings.Contains(h, "shortcuts") {
-		t.Fatalf("expected idle hint, got %q", h)
+	for _, test := range []struct {
+		name  string
+		width int
+	}{
+		{name: "medium", width: 80},
+		{name: "full", width: 100},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			idle := m
+			idle.width = test.width
+
+			// Idle, empty composer, managed mode -> the discoverability hint shows.
+			hint := plainRender(t, idle.composerIdleHint())
+			if !strings.Contains(hint, "shortcuts") {
+				t.Fatalf("expected idle hint, got %q", hint)
+			}
+			if strings.Contains(hint, "sidebar") {
+				t.Fatalf("empty sidebar should not be advertised, got %q", hint)
+			}
+
+			withSidebar := idle
+			withSidebar.plan.steps = []planStep{{content: "inspect footer", status: "in_progress"}}
+			if hint := plainRender(t, withSidebar.composerIdleHint()); !strings.Contains(hint, "Ctrl+B sidebar") {
+				t.Fatalf("available sidebar should be advertised, got %q", hint)
+			}
+			withSidebar.sidebarHidden = true
+			if hint := plainRender(t, withSidebar.composerIdleHint()); !strings.Contains(hint, "Ctrl+B sidebar") {
+				t.Fatalf("collapsed sidebar should keep its restore shortcut, got %q", hint)
+			}
+		})
 	}
 	// Hidden during a run.
 	busy := m