fix(app): a sign-out or deletion that failed says so, its tile showing it under way

The account's tiles show a spinner on Sign out or Delete account while it
runs, start neither again meanwhile, and say once, in a snack bar, why one
failed ("Couldn't delete your account: the instance wasn't reached. Try
again."; "Couldn't sign out on this device. Try again."), in English and
German. The session gate no longer builds the person's app anew for that:
only the tiles follow it.

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

packages/halkyon_app/lib/l10n/halkyon_app_de.arb

@@ -39,6 +39,8 @@
   "accountSignOutTitle": "Abmelden?",
   "accountDelete": "Konto löschen",
   "accountDeleteTitle": "Dein Konto löschen?",
+  "accountSignOutFailed": "Abmelden auf diesem Gerät hat nicht geklappt. Versuch es noch einmal.",
+  "accountDeleteFailed": "Dein Konto wurde nicht gelöscht: Die Instanz war nicht erreichbar. Versuch es noch einmal.",
   "aboutSourceCode": "Der Quellcode dessen, was diese Instanz ausführt:",
   "aboutSourceUnreachable": "Diese Instanz war nicht erreichbar, um nach ihrem Quellcode zu fragen.",
   "sessionUnreachable": "Der Server war nicht erreichbar.",

packages/halkyon_app/lib/l10n/halkyon_app_en.arb

@@ -149,6 +149,8 @@
   "accountSignOutTitle": "Sign out?",
   "accountDelete": "Delete account",
   "accountDeleteTitle": "Delete your account?",
+  "accountSignOutFailed": "Couldn't sign out on this device. Try again.",
+  "accountDeleteFailed": "Couldn't delete your account: the instance wasn't reached. Try again.",
   "aboutSourceCode": "The source of what this instance runs:",
   "aboutSourceUnreachable": "Couldn't reach this instance to ask where its source is.",
   "sessionUnreachable": "Couldn't reach the server.",

packages/halkyon_app/lib/l10n/halkyon_app_localizations.dart

@@ -337,6 +337,18 @@ abstract class HalkyonAppLocalizations {
   /// **'Delete your account?'**
   String get accountDeleteTitle;
 
+  /// No description provided for @accountSignOutFailed.
+  ///
+  /// In en, this message translates to:
+  /// **'Couldn\'t sign out on this device. Try again.'**
+  String get accountSignOutFailed;
+
+  /// No description provided for @accountDeleteFailed.
+  ///
+  /// In en, this message translates to:
+  /// **'Couldn\'t delete your account: the instance wasn\'t reached. Try again.'**
+  String get accountDeleteFailed;
+
   /// No description provided for @aboutSourceCode.
   ///
   /// In en, this message translates to:

packages/halkyon_app/lib/l10n/halkyon_app_localizations_de.dart

@@ -155,6 +155,14 @@ class HalkyonAppLocalizationsDe extends HalkyonAppLocalizations {
   @override
   String get accountDeleteTitle => 'Dein Konto löschen?';
 
+  @override
+  String get accountSignOutFailed =>
+      'Abmelden auf diesem Gerät hat nicht geklappt. Versuch es noch einmal.';
+
+  @override
+  String get accountDeleteFailed =>
+      'Dein Konto wurde nicht gelöscht: Die Instanz war nicht erreichbar. Versuch es noch einmal.';
+
   @override
   String get aboutSourceCode =>
       'Der Quellcode dessen, was diese Instanz ausführt:';

packages/halkyon_app/lib/l10n/halkyon_app_localizations_en.dart

@@ -155,6 +155,14 @@ class HalkyonAppLocalizationsEn extends HalkyonAppLocalizations {
   @override
   String get accountDeleteTitle => 'Delete your account?';
 
+  @override
+  String get accountSignOutFailed =>
+      'Couldn\'t sign out on this device. Try again.';
+
+  @override
+  String get accountDeleteFailed =>
+      'Couldn\'t delete your account: the instance wasn\'t reached. Try again.';
+
   @override
   String get aboutSourceCode => 'The source of what this instance runs:';
 

packages/halkyon_app/lib/src/auth/widget/account_tiles.dart

@@ -37,15 +37,19 @@ class const AccountTiles({
   Widget build(BuildContext context) {
     final l10n = HalkyonAppLocalizations.of(context);
     final theme = Theme.of(context);
-    final identified = switch (context.watch<SessionBloc>().state) {
-      SessionStateActive(:final person) => person.isIdentified,
-      _ => false,
+    final session = context.watch<SessionBloc>().state;
+    final (identified, busy) = switch (session) {
+      SessionStateActive(:final person, :final busy) => (
+        person.isIdentified,
+        busy,
+      ),
+      _ => (false, null),
     };
     final instances = InstanceScope.maybeOf(context);
     final instance =
         instances?.choice.current?.name ??
         AppScope.of<AppDependencies<Disposable>>(context).serverName;
-    return Column(
+    final column = Column(
       mainAxisSize: MainAxisSize.min,
       crossAxisAlignment: CrossAxisAlignment.stretch,
       children: [
@@ -71,10 +75,14 @@ class const AccountTiles({
             subtitle: Text(instances.choice.current?.name ?? ''),
             onTap: () => showAccountSwitcher(context),
           ),
+        // While one is under way, its tile says so and neither starts again.
         ListTile(
           leading: const Icon(LucideIcons.logOut),
           title: Text(l10n.accountSignOut),
-          onTap: () => _signOut(context),
+          trailing: busy == SessionAction.signOut
+              ? const ButtonLoadingIndicator()
+              : null,
+          onTap: busy == null ? () => _signOut(context) : null,
         ),
         ListTile(
           leading: Icon(LucideIcons.trash2, color: theme.colorScheme.error),
@@ -82,10 +90,30 @@ class const AccountTiles({
             l10n.accountDelete,
             style: TextStyle(color: theme.colorScheme.error),
           ),
-          onTap: () => _delete(context),
+          trailing: busy == SessionAction.delete
+              ? const ButtonLoadingIndicator()
+              : null,
+          onTap: busy == null ? () => _delete(context) : null,
         ),
       ],
     );
+    // A failure keeps the person here: said once, as it happens.
+    return BlocListener<SessionBloc, SessionState>(
+      listenWhen: (previous, current) =>
+          current is SessionStateActive &&
+          current.problem != null &&
+          previous != current,
+      listener: (context, state) {
+        final text = switch ((state as SessionStateActive).problem!) {
+          SessionProblem.signOutFailed => l10n.accountSignOutFailed,
+          SessionProblem.deleteFailed => l10n.accountDeleteFailed,
+        };
+        ScaffoldMessenger.maybeOf(
+          context,
+        )?.showSnackBar(SnackBar(content: Text(text)));
+      },
+      child: column,
+    );
   }
 
   /// Signs out; an anonymous account can't be signed into again, so signing

packages/halkyon_app/lib/src/auth/widget/session_gate.dart

@@ -39,6 +39,12 @@ class const SessionGate({
       AppScope.of(context).signedOut,
     )..add(const SessionEventStarted()),
     child: BlocBuilder<SessionBloc, SessionState>(
+      // A sign-out or deletion under way, or failed, leaves the person's
+      // app as it is: the account's tiles show it.
+      buildWhen: (previous, current) =>
+          !(previous is SessionStateActive &&
+              current is SessionStateActive &&
+              previous.person == current.person),
       builder: (context, state) => switch (state) {
         SessionStateLoading() => PlainApp(
           look: look(context),

packages/halkyon_app/lib/src/testing/fake_auth_gateway.dart

@@ -36,6 +36,10 @@ class FakeAuthGateway({var AuthStatus _status = const SignedOut()})
   /// delete nothing.
   Exception? deletionError;
 
+  /// While set, deletions of the account wait for it, as for an instance
+  /// slow to answer.
+  Completer<void>? deletionWaits;
+
   /// Whether the instance offers GitHub sign-in.
   bool offersGitHub = true;
 
@@ -99,6 +103,9 @@ class FakeAuthGateway({var AuthStatus _status = const SignedOut()})
   @override
   Future<void> deleteAccount() async {
     accountDeletions++;
+    if (deletionWaits case final wait?) {
+      await wait.future;
+    }
     if (deletionError case final error?) {
       throw error;
     }