put shiny input elements in the navbar using flexdashboard

I have a shiny app using flexdashboard and I'd like to put a simple shiny boolean input element (eg, switch or checkbox) into the navbar (think, "dark mode switch" or the like).

Here's my document:

---
title: "Test"
output: flexdashboard::flex_dashboard
runtime: shiny
---

Column {.sidebar}
-----------------------------------------------------------------------

Filler

```{r}
checkboxInput("cb", label = "Checkbox")

textInput("tb", label = "Text")
```


Column
-----------------------------------------------------------------------

### Column

This is a column.

which renders like this:

How can I put the checkbox into the navbar header (say, before the title "Test")? Is there an easy way besides, say, moving it with javascript when the page loads?