Add link to buymeacoffee for donations

lib/l10n/app_en.arb

@@ -483,6 +483,8 @@
   "@aboutTranslationText": {
     "description": "Text for translation section in the about dialog"
   },
+  "aboutDonateTitle": "Donate",
+  "aboutDonateText": "Buy us a coffee to help the project, pay for server costs, and keep us fueled",
   "calendar": "Calendar",
   "@calendar": {},
   "goToToday": "Go to today",

lib/widgets/core/about.dart

@@ -59,6 +59,7 @@ class AboutEntry extends StatelessWidget {
 
 class AboutPage extends StatefulWidget {
   static String routeName = '/AboutPage';
+
   const AboutPage({super.key});
 
   @override
@@ -158,6 +159,13 @@ class _AboutPageState extends State<AboutPage> {
               url: 'https://hosted.weblate.org/engage/wger',
               icon: const Icon(Icons.translate),
             ),
+            const SizedBox(height: 10),
+            AboutEntry(
+              title: AppLocalizations.of(context).aboutDonateTitle,
+              content: AppLocalizations.of(context).aboutDonateText,
+              url: 'https://www.buymeacoffee.com/wger',
+              icon: const Icon(FontAwesomeIcons.moneyBill1),
+            ),
             ListTile(
               leading: const Icon(Icons.article),
               title: const Text('View Licenses'),