feat(app): what's new after an update, drafted by the release tool (ADR 0030, D61)

halkyon_app's WhatsNew reads what each release changed from the app's
assets/whats_new/ (<version>.<language>.txt, English and German, a change
a line): after an update a sheet lists every release since the one the
device showed last, newest first, once; Settings shows the running
version's again, above About. Nothing on a fresh install.

tool/release.dart drafts the missing texts from the commits that count
after "Go on?" (German marked TRANSLATE:), opens them in the editor until
they fit (no mark left, F-Droid's 500 characters) and commits them with
the version. The English is the Forgejo notes' What's new, each language
F-Droid's changelog of the build, written at publishing and copied in by
tool/fdroid_repo.sh. Learn and Train bundle their texts, Learn's 0.22.0
and Train's 0.1.0 written to start.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/learn/halkyon_learn_flutter/lib/main.dart

@@ -1,5 +1,6 @@
 import 'dart:io';
 
+import 'package:flutter/services.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:halkyon_app/halkyon_app.dart';
 import 'package:halkyon_learn_flutter/src/app/app_icon_license.dart';
@@ -42,15 +43,24 @@ Future<void> main() async {
   );
   await instances.load(usedBefore: device.storage.usedBefore());
   runApp(
-    InstanceGate(
-      frame: learnFrame,
-      choice: instances,
-      // Only an instance of Halkyon Learn: one of another Halkyon app's
-      // answers too, but holds nothing of this app's.
-      checker: ServerpodInstanceChecker(app: 'learn'),
-      open: (instance) => Dependencies.create(instance, device),
-      readLook: () async => (await device.deviceSettingsStore.read()).look,
-      app: const LearnSessions(),
+    WhatsNewScope(
+      whatsNew: WhatsNew(
+        AssetWhatsNewSource(rootBundle),
+        FileWhatsNewStore(File(p.join(device.support, 'whats_new.json'))),
+        version: device.appVersion.version,
+      ),
+      // An instance chosen before: the app ran on this device already.
+      usedBefore: instances.current != null,
+      child: InstanceGate(
+        frame: learnFrame,
+        choice: instances,
+        // Only an instance of Halkyon Learn: one of another Halkyon app's
+        // answers too, but holds nothing of this app's.
+        checker: ServerpodInstanceChecker(app: 'learn'),
+        open: (instance) => Dependencies.create(instance, device),
+        readLook: () async => (await device.deviceSettingsStore.read()).look,
+        app: const LearnSessions(),
+      ),
     ),
   );
 }

apps/learn/halkyon_learn_flutter/lib/src/core/router/app_shell.dart

@@ -1,4 +1,5 @@
 import 'package:go_router/go_router.dart';
+import 'package:halkyon_app/halkyon_app.dart';
 import 'package:halkyon_learn_flutter/l10n/app_localizations.dart';
 import 'package:halkyon_ui/halkyon_ui.dart';
 import 'package:lucide_icons_flutter/lucide_icons.dart';
@@ -40,26 +41,29 @@ class const AppShell({
             child: Icon(data),
           )
         : Icon(data);
-    return NavigationFrame(
-      appName: l10n.appTitle,
-      // The kingfisher has a white background, which the frame's rounded
-      // tile keeps reading on light and dark rails alike.
-      icon: const AssetImage('assets/icon/halkyon_icon.png'),
-      selectedIndex: navigationShell.currentIndex,
-      onSelected: (index) => navigationShell.goBranch(
-        index,
-        initialLocation: index == navigationShell.currentIndex,
+    // After an update, what's new shows once.
+    return WhatsNewOnUpdate(
+      child: NavigationFrame(
+        appName: l10n.appTitle,
+        // The kingfisher has a white background, which the frame's rounded
+        // tile keeps reading on light and dark rails alike.
+        icon: const AssetImage('assets/icon/halkyon_icon.png'),
+        selectedIndex: navigationShell.currentIndex,
+        onSelected: (index) => navigationShell.goBranch(
+          index,
+          initialLocation: index == navigationShell.currentIndex,
+        ),
+        hidesNavigationBar: hidesNavigationBar,
+        destinations: [
+          for (final destination in destinations)
+            (
+              label: destination.label,
+              icon: icon(destination, destination.icon),
+              selectedIcon: icon(destination, destination.selectedIcon),
+            ),
+        ],
+        child: navigationShell,
       ),
-      hidesNavigationBar: hidesNavigationBar,
-      destinations: [
-        for (final destination in destinations)
-          (
-            label: destination.label,
-            icon: icon(destination, destination.icon),
-            selectedIcon: icon(destination, destination.selectedIcon),
-          ),
-      ],
-      child: navigationShell,
     );
   }
 }

apps/learn/halkyon_learn_flutter/lib/src/feature/settings/widget/settings_screen.dart

@@ -106,10 +106,17 @@ class const SettingsScreen({super.key}) extends StatelessWidget {
                   const SizedBox(height: 12),
                   SectionCard(
                     padding: const EdgeInsets.symmetric(vertical: 8),
-                    child: ListTile(
-                      leading: const Icon(LucideIcons.info),
-                      title: Text(l10n.settingsAbout),
-                      onTap: () => showAbout(context),
+                    child: Column(
+                      children: [
+                        // What changed in this version, as shown once after
+                        // the update (halkyon_app's).
+                        const WhatsNewTile(),
+                        ListTile(
+                          leading: const Icon(LucideIcons.info),
+                          title: Text(l10n.settingsAbout),
+                          onTap: () => showAbout(context),
+                        ),
+                      ],
                     ),
                   ),
                   const SizedBox(height: 24),