Dash: indicator telltales as Material triangle icons (◀▶ stay emoji on Android even with U+FE0E)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

lib/dash.dart

@@ -140,11 +140,13 @@ class DashPage extends StatelessWidget {
                                 isWarning: () => (coolant.number ?? 0) > 105,
                               ),
                               Telltale(
-                                label: '◀\uFE0E',
+                                label: 'LEFT',
+                                icon: Icons.arrow_left,
                                 reading: r('indicator_left'),
                               ),
                               Telltale(
-                                label: '▶\uFE0E',
+                                label: 'RIGHT',
+                                icon: Icons.arrow_right,
                                 reading: r('indicator_right'),
                               ),
                               Telltale(
@@ -188,11 +190,15 @@ class Telltale extends StatelessWidget {
     super.key,
     required this.label,
     required this.reading,
+    this.icon,
     this.warn = false,
     this.flex = 1,
   });
 
   final String label;
+
+  /// Drawn instead of the label when set. Glyphs like ◀ ▶ come out as emoji on Android.
+  final IconData? icon;
   final Reading reading;
   final bool warn;
   final int flex;
@@ -210,6 +216,16 @@ class Telltale extends StatelessWidget {
       child: LayoutBuilder(
         builder: (context, c) {
           final size = c.maxHeight * 0.3;
+          if (icon != null && !missing) {
+            return Center(
+              child: Icon(
+                icon,
+                size: c.maxHeight * 0.7,
+                color: color,
+                semanticLabel: label,
+              ),
+            );
+          }
           return Center(
             child: Text(
               missing ? '—' : label,