Dash: DIN 1451 opt-in per widget (hudFont), GNSS compass, rei by default; widget catalogue

From smart-serow: the DIN 1451 face (Alte DIN 1451 Mittelschrift, via gps-speedo)
and GpsCompass. A cosmetic font is opt-in: widgets name hudFont in their own
TextStyle, the rest keeps the basic font (CJK). Boxes and telltales shrink long
labels instead of wrapping. Telltale and Reading get their own files;
lib/README.md catalogues folders and widgets like smart-serow's.

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

lib/dash.dart

@@ -6,35 +6,14 @@
 import 'package:flutter/material.dart';
 
 import 'boundary.dart';
+import 'reading.dart';
 import 'theme/palette.dart';
 import 'widgets/accel_graph.dart';
+import 'widgets/gps_compass.dart';
 import 'widgets/stat_box.dart';
+import 'widgets/telltale.dart';
 import 'widgets/whiskey_mark.dart';
 
-/// One signal's current state, as the dash needs it.
-class Reading {
-  const Reading(this.value, {this.dim = false});
-
-  /// The value, or null when missing or known-without-value.
-  final Object? value;
-
-  /// Missing or stale: drawn in subdued.
-  final bool dim;
-
-  static Reading of(Boundary b, String name) {
-    final e = b.signals[name];
-    if (e is! Map) return const Reading(null, dim: true);
-    final q = e['quality'] as String? ?? 'ok';
-    return Reading(e['value'], dim: q != 'ok' || e['value'] == null);
-  }
-
-  double? get number => value is num ? (value as num).toDouble() : null;
-  bool get on => value == true;
-
-  String fixed([int decimals = 0]) =>
-      number == null ? '—' : number!.toStringAsFixed(decimals);
-}
-
 class DashPage extends StatelessWidget {
   const DashPage({super.key, required this.boundary, required this.themes});
   final Boundary boundary;
@@ -54,6 +33,13 @@ class DashPage extends StatelessWidget {
         final coolant = r('obd_coolant_temp_c');
         final lat = r('imu_accel_lat_g');
         final lon = r('imu_accel_lon_g');
+        // The compass's states, from gnss_fix: none → acquiring, 2d/3d → fix, missing → none known.
+        final fix = r('gnss_fix');
+        final gpsState = fix.value == null
+            ? null
+            : fix.value == 'none'
+            ? 'acquiring'
+            : 'fix';
 
         return Scaffold(
           backgroundColor: p.background,
@@ -139,6 +125,12 @@ class DashPage extends StatelessWidget {
                                 dim: coolant.dim,
                                 isWarning: () => (coolant.number ?? 0) > 105,
                               ),
+                              Expanded(
+                                child: GpsCompass(
+                                  heading: r('gnss_heading_deg').number,
+                                  gpsState: gpsState,
+                                ),
+                              ),
                               Telltale(
                                 label: 'LEFT',
                                 icon: Icons.arrow_left,
@@ -183,66 +175,6 @@ class DashPage extends StatelessWidget {
   }
 }
 
-/// An on/off lamp in the boxed pattern: the label is the lamp. Lit in foreground
-/// (highlight when [warn]), dark in subdued; missing shows as a dash.
-class Telltale extends StatelessWidget {
-  const Telltale({
-    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;
-
-  @override
-  Widget build(BuildContext context) {
-    final p = AppTheme.of(context);
-    final missing = reading.value == null;
-    final lit = reading.on && !reading.dim;
-    final color = lit
-        ? (warn ? p.highlight : p.foreground)
-        : p.subdued.withValues(alpha: missing ? 0.35 : 0.6);
-    return Expanded(
-      flex: flex,
-      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,
-              style: TextStyle(
-                fontSize: size,
-                fontWeight: lit ? FontWeight.w700 : FontWeight.w400,
-                color: color,
-                letterSpacing: 1,
-              ),
-            ),
-          );
-        },
-      ),
-    );
-  }
-}
-
 /// The dash's own thin top line: link state, back, and the dark/bright switch.
 class _DashBar extends StatelessWidget {
   const _DashBar({required this.boundary, required this.themes});