Fix ROBINS-E manual data entry (Add a new study does nothing)

[Copilot]

Clicking "Add a new study" with ROBINS-E selected was a no-op — the observeEvent(input$enter_manually) handler had branches for ROB2, ROB2-Cluster, ROBINS-I, and QUADAS-2, but ROBINS-E was never added.

Change

• robvisapp/app.R: Added the missing ROBINS-E branch, initializing the editable data frame with the correct 7-domain structure:

if (input$tool == "ROBINS-E") {
  rv$data = data.frame(
    Study   = "Click to edit",
    D1      = "Click to edit",
    D2      = "Click to edit",
    D3      = "Click to edit",
    D4      = "Click to edit",
    D5      = "Click to edit",
    D6      = "Click to edit",
    D7      = "Click to edit",
    Overall = "Click to edit",
    Weights = 1,
    stringsAsFactors = FALSE
  )
  rv$new_row = rv$data
}