Refactor: safely extract scalar station details from tibble for state broadcasting.

server.R

@@ -31,9 +31,10 @@ server <- function(input, output, session) {
     # Helper: Broadcast current state to parent page
     broadcast_state <- function(view_override = NULL) {
         st <- selected_station()
-        station_id <- if (!is.null(st)) st$ID else NULL
-        station_name <- if (!is.null(st)) st$DisplayName else NULL
-        prefecture <- if (!is.null(st)) st$PrecName else NULL
+        # Extract scalar values from tibble row
+        station_id <- if (!is.null(st) && nrow(st) > 0) as.character(st$ID[[1]]) else NULL
+        station_name <- if (!is.null(st) && nrow(st) > 0) as.character(st$DisplayName[[1]]) else NULL
+        prefecture <- if (!is.null(st) && nrow(st) > 0 && !is.na(st$PrecName[[1]])) as.character(st$PrecName[[1]]) else NULL
         resolution <- input$data_resolution
         
         # Determine current view