user: hook up screen_legend from ScreenView::label()

Build legend string from actual screen labels instead of hardcoded
constant. Computed once at startup via OnceLock, accessible from
all screen draw methods.

Co-Authored-By: Kent Overstreet <kent.overstreet@linux.dev>

src/user/mod.rs

@@ -28,10 +28,24 @@ use std::io;
 
 use crate::user::ui_channel::{ContextInfo, SharedContextState, StatusInfo};
 
-/// Build the screen legend from the screen table.
+/// Build the screen legend from screen labels.
+pub(crate) fn screen_legend_from(interact: &dyn ScreenView, screens: &[Box<dyn ScreenView>]) -> String {
+    let mut parts = vec![format!("F1={}", interact.label())];
+    for (i, s) in screens.iter().enumerate() {
+        parts.push(format!("F{}={}", i + 2, s.label()));
+    }
+    format!(" {} ", parts.join("  "))
+}
+
+// Cached legend — set once at startup by event_loop
+static SCREEN_LEGEND: std::sync::OnceLock<String> = std::sync::OnceLock::new();
+
+pub(crate) fn set_screen_legend(legend: String) {
+    let _ = SCREEN_LEGEND.set(legend);
+}
+
 pub(crate) fn screen_legend() -> String {
-    // Built from the SCREENS table in event_loop
-    " F1=interact  F2=conscious  F3=subconscious  F4=unconscious  F5=thalamus ".to_string()
+    SCREEN_LEGEND.get().cloned().unwrap_or_default()
 }
 
 pub(crate) fn strip_ansi(text: &str) -> String {