Allow onclick HTML elements in append_chat

I have a shiny app where I use shinychat as a frontend for a RAG system. As I want to display sources to the users with nice UX, I would create button links that set some JS value using Shiny.setInputValue(), which is picked up and the appropriate source is rendered elsewhere.

The problem is that somehow somewhere shinychat swallows the onclick element:

library(shiny)

# create sample content
sample_content <- span(
  "This is the sample source content.",
  tags$button(
    class = "btn btn-sm btn-link",
    onclick = "Shiny.setInputValue('from_js', {p: 1, v: Math.random()})",
    "Sample from Page 1"
  )
)

ui <- bslib::page_fillable(
  bslib::layout_columns(
    bslib::card(
      bslib::card_header("Here it is rendered with onclick => works"),
      sample_content
    ),
    bslib::card(
      bslib::card_header("Here it is rendered with shinychat::chat_append => does not work, no onlclick!"),
      shinychat::chat_ui("out")
    )
  )
)

server <- function(input, output, session) {
  shinychat::chat_append(
    "out",
    sample_content,
   session = session
  )
  
  # see if there are any inputs sent from the UI
  shiny::observe({
    print("From JS:")
    print(input$from_js)
    cat("===========\n")
  })
}

shinyApp(ui, server)

When I click on the "raw HTML" button (left side), I see something like this:

[1] "From JS:"
$p
[1] 1

$v
[1] 0.3141059

===========
[1] "From JS:"
$p
[1] 1

$v
[1] 0.6320509

when I click on the shinychat renderd button (right side) nothing is shown, when I inspect the button, I see this HTML source code without the onclick functionality

<button class="btn btn-sm btn-link">Sample from Page 1</button>

is there any way for me as a user to change this behavior or is there another workaround to setting some values from the output of the chat system?

Start at the shinychat::chat_append entry point and compare its rendered HTML with the direct UI rendering shown in the report. Reproduce the example, inspect where the onclick attribute is removed, and verify that appended button elements preserve the handler without breaking existing chat rendering.