Make comment box trigger options configurable via config.yaml

[Copilot]

The voting UI's comment box visibility was hardcoded to trigger only for diff_var and none_of_above. This PR makes that list configurable so operators can show the comment box for any combination of radio options (or all of them).

Changes

• config.yaml — New comment_trigger_options field:

  comment_trigger_options:
  - diff_var
  - none_of_above

• load_config.R

  • Defaults to c("diff_var", "none_of_above") when field is absent (backward compatible)
  • Validates all listed values exist in radio_options2val_map; errors on unknown values

• mod_voting.R (UI) — JS condition for conditionalPanel is now generated from config; empty list produces "false" (panel hidden)

  comment_condition <- paste(
    sapply(cfg$comment_trigger_options, function(opt) {
      sprintf("input['%s'] == '%s'", ns("agreement"), opt)
    }),
    collapse = " || "
  )

• mod_voting.R (server) — Comment persistence check replaced from hardcoded || comparisons to %in% cfg$comment_trigger_options