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/theme/palette.dart

@@ -6,17 +6,18 @@
 //   final p = AppTheme.of(context);
 //   color: p.foreground
 //
-// Pick the theme at build time: `--dart-define=YUKART_THEME=rei` (default: default).
+// Pick the theme at build time: `--dart-define=YUKART_THEME=default` (default: rei, smart-serow's).
 
 import 'dart:convert';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 
-const themeName = String.fromEnvironment(
-  'YUKART_THEME',
-  defaultValue: 'default',
-);
+/// The HUD face (smart-serow's DIN 1451). Opt-in: a widget names it in its own
+/// TextStyle; everything else keeps the basic font, which covers CJK where DIN does not.
+const hudFont = 'DIN1451';
+
+const themeName = String.fromEnvironment('YUKART_THEME', defaultValue: 'rei');
 
 /// One variant (dark or bright) of a theme.
 class Palette {