feat(base)!: removing a profile makes it private (ADR 0020, D27)

Every account keeps a handle now, so removing a public profile no
longer deletes it and frees the handle: it takes away what the profile
shows and leaves it private, as a profile is until its person goes
public (D5).

- `profile.remove` and the register's `removeProfile` (members ask the
  register) empty the display name, bio, links with their checks and
  the avatar, keep the row with its handle, and return what is left,
  null for none. `/@handle` and `profiles.byHandle` then answer as for
  a handle nobody has. Once the person has published, removing is
  refused as before.
- Learn: the profile form starts afresh from what is left, "Remove
  profile" shows only while something is filled in, and the dialog says
  the handle stays.
- The module's README and ADR 0020 amended.

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/l10n/app_de.arb

@@ -514,7 +514,7 @@
   "publicProfileHandleConfirmChange": "Ändern",
   "publicProfileRemove": "Profil entfernen",
   "publicProfileRemoveTitle": "Dein öffentliches Profil entfernen?",
-  "publicProfileRemoveMessage": "Dein Handle wird für andere frei.",
+  "publicProfileRemoveMessage": "Anzeigename, Text über dich, Links und Bild werden entfernt. Dein Handle bleibt deins und privat, bis du dein Profil wieder ausfüllst oder etwas veröffentlichst.",
   "publicProfileRemoved": "Profil entfernt.",
   "publicProfileFailed": "Die Instanz ist nicht erreichbar. Versuche es erneut.",
   "publicProfileUnreachable": "Dein öffentliches Profil ist gerade nicht erreichbar.",

apps/learn/halkyon_learn_flutter/lib/l10n/app_en.arb

@@ -585,7 +585,7 @@
   "publicProfileHandleConfirmChange": "Change",
   "publicProfileRemove": "Remove profile",
   "publicProfileRemoveTitle": "Remove your public profile?",
-  "publicProfileRemoveMessage": "Your handle becomes free for others to take.",
+  "publicProfileRemoveMessage": "Your display name, bio, links and picture are removed. Your handle stays yours and private until you fill in your profile again or publish something.",
   "publicProfileRemoved": "Profile removed.",
   "publicProfileFailed": "Couldn't reach the instance. Try again.",
   "publicProfileUnreachable": "Your public profile can't be reached right now.",

apps/learn/halkyon_learn_flutter/lib/l10n/app_localizations.dart

@@ -3085,7 +3085,7 @@ abstract class AppLocalizations {
   /// No description provided for @publicProfileRemoveMessage.
   ///
   /// In en, this message translates to:
-  /// **'Your handle becomes free for others to take.'**
+  /// **'Your display name, bio, links and picture are removed. Your handle stays yours and private until you fill in your profile again or publish something.'**
   String get publicProfileRemoveMessage;
 
   /// No description provided for @publicProfileRemoved.

apps/learn/halkyon_learn_flutter/lib/l10n/app_localizations_de.dart

@@ -1869,7 +1869,8 @@ class AppLocalizationsDe extends AppLocalizations {
   String get publicProfileRemoveTitle => 'Dein öffentliches Profil entfernen?';
 
   @override
-  String get publicProfileRemoveMessage => 'Dein Handle wird für andere frei.';
+  String get publicProfileRemoveMessage =>
+      'Anzeigename, Text über dich, Links und Bild werden entfernt. Dein Handle bleibt deins und privat, bis du dein Profil wieder ausfüllst oder etwas veröffentlichst.';
 
   @override
   String get publicProfileRemoved => 'Profil entfernt.';

apps/learn/halkyon_learn_flutter/lib/l10n/app_localizations_en.dart

@@ -1852,7 +1852,7 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get publicProfileRemoveMessage =>
-      'Your handle becomes free for others to take.';
+      'Your display name, bio, links and picture are removed. Your handle stays yours and private until you fill in your profile again or publish something.';
 
   @override
   String get publicProfileRemoved => 'Profile removed.';

apps/learn/halkyon_learn_flutter/lib/src/feature/profile/bloc/public_profile_bloc.dart

@@ -216,9 +216,12 @@ class PublicProfileBloc(final ProfileRepository _profiles)
     if (state case PublicProfileStateReady(:final profile?, saving: false)) {
       emit(PublicProfileStateReady(profile: profile, saving: true));
       try {
-        await _profiles.remove();
+        final left = await _profiles.remove();
         emit(
-          const PublicProfileStateReady(outcome: PublicProfileOutcome.removed),
+          PublicProfileStateReady(
+            profile: left,
+            outcome: PublicProfileOutcome.removed,
+          ),
         );
       } on ProfileRefused catch (refused) {
         emit(

apps/learn/halkyon_learn_flutter/lib/src/feature/profile/data/profile_gateway.dart

@@ -25,9 +25,10 @@ abstract interface class ProfileGateway() {
   /// when it can.
   Future<ProfileProblem?> checkHandle(String handle);
 
-  /// Removes the person's public profile. Throws [ProfileRefused] once they
-  /// have published.
-  Future<void> remove();
+  /// Removes what the person's public profile shows, making it private
+  /// again with its handle (ADR 0020, D27); returns what is left, null while
+  /// they have none. Throws [ProfileRefused] once they have published.
+  Future<PublicProfile?> remove();
 
   /// Shows [png] as the person's avatar; returns the profile with it.
   /// Throws [ProfileRefused] for anything but a PNG of at most 1 MB.

apps/learn/halkyon_learn_flutter/lib/src/feature/profile/data/profile_repository.dart

@@ -43,9 +43,10 @@ class ProfileRepository(
   Future<ProfileProblem?> checkHandle(String handle) =>
       _gateway.checkHandle(handle.trim());
 
-  /// Removes the person's public profile. Throws [ProfileRefused] once they
-  /// have published.
-  Future<void> remove() => _gateway.remove();
+  /// Removes what the person's public profile shows, making it private
+  /// again with its handle (ADR 0020, D27); returns what is left, null while
+  /// they have none. Throws [ProfileRefused] once they have published.
+  Future<PublicProfile?> remove() => _gateway.remove();
 
   /// Shows [picture] (a PNG, JPEG, WebP or GIF) as the person's avatar,
   /// drawn anew as a square PNG ([avatarPng]): metadata such as where a

apps/learn/halkyon_learn_flutter/lib/src/feature/profile/data/serverpod_profile_gateway.dart

@@ -51,7 +51,12 @@ class ServerpodProfileGateway(final protocol.Client _client)
       };
 
   @override
-  Future<void> remove() => _refusing(_profiles.remove);
+  Future<PublicProfile?> remove() => _refusing(
+    () async => switch (await _profiles.remove()) {
+      final profile? => _profile(profile),
+      null => null,
+    },
+  );
 
   @override
   Future<PublicProfile> setAvatar(Uint8List png) => _refusing(

apps/learn/halkyon_learn_flutter/lib/src/feature/profile/widget/public_profile_section.dart

@@ -12,7 +12,8 @@ import 'package:material_ui/material_ui.dart';
 
 /// The person's public profile (ADR 0005, rule 2), in the Profile tab: what
 /// it is for, and a form of its handle, display name, bio and links that
-/// saves as it is written; a way to remove it until the person publishes.
+/// saves as it is written; a way to remove what it shows, making it private
+/// with its handle (ADR 0020, D27), until the person publishes.
 class const PublicProfileSection({super.key}) extends StatelessWidget {
   @override
   Widget build(BuildContext context) => BlocProvider(
@@ -23,7 +24,16 @@ class const PublicProfileSection({super.key}) extends StatelessWidget {
   );
 }
 
-class const _Section() extends StatelessWidget {
+class const _Section() extends StatefulWidget {
+  @override
+  State<_Section> createState() => _SectionState();
+}
+
+class _SectionState() extends State<_Section> {
+  /// How often the profile was removed here: the form starts afresh each
+  /// time, from what is left.
+  var _removals = 0;
+
   @override
   Widget build(BuildContext context) {
     final l10n = AppLocalizations.of(context);
@@ -35,6 +45,11 @@ class const _Section() extends StatelessWidget {
           now.outcome != null &&
           now.outcome != PublicProfileOutcome.saved,
       listener: (context, state) {
+        if (state case PublicProfileStateReady(
+          outcome: PublicProfileOutcome.removed,
+        )) {
+          setState(() => _removals++);
+        }
         final message = switch (state) {
           PublicProfileStateReady(outcome: PublicProfileOutcome.removed) =>
             l10n.publicProfileRemoved,
@@ -107,7 +122,7 @@ class const _Section() extends StatelessWidget {
               _ProfileForm(
                 // Kept while the person writes, as saves come back; afresh
                 // once a profile is made or removed.
-                key: ValueKey(profile != null),
+                key: ValueKey((profile != null, _removals)),
                 profile: profile,
                 saving: saving,
                 checkingLinks: checkingLinks,
@@ -272,6 +287,14 @@ class _ProfileFormState() extends State<_ProfileForm> {
     _saveIfChanged();
   }
 
+  /// Whether [profile] shows anything removing would take away: with the
+  /// handle alone it is private already (ADR 0020, D5).
+  static bool _showsSomething(PublicProfile profile) =>
+      profile.displayName.isNotEmpty ||
+      profile.bio.isNotEmpty ||
+      profile.links.isNotEmpty ||
+      profile.avatarUrl != null;
+
   Future<void> _remove() async {
     final l10n = AppLocalizations.of(context);
     final bloc = context.read<PublicProfileBloc>();
@@ -450,7 +473,7 @@ class _ProfileFormState() extends State<_ProfileForm> {
             ),
           ),
         ],
-        if (profile != null && !fixed) ...[
+        if (profile != null && !fixed && _showsSomething(profile)) ...[
           const SizedBox(height: 16),
           Align(
             alignment: AlignmentDirectional.centerStart,

apps/learn/halkyon_learn_flutter/test/feature/profile/public_profile_test.dart

@@ -212,25 +212,56 @@ void main() {
     expect(find.text('Remove profile'), findsNothing);
   });
 
-  testWidgets('removing a profile asks first, then frees its handle', (
-    tester,
-  ) async {
+  testWidgets('removing a profile asks first, then makes it private: the '
+      'handle stays, what was filled in goes (ADR 0020, D27)', (tester) async {
     final profiles = FakeProfileGateway(
       profile: const PublicProfile(
         handle: 'raisondetredev',
         address: 'raisondetredev@halkyon.eu',
+        displayName: 'Raison',
+        bio: 'Learning Japanese.',
+        links: ['https://halkyon.app'],
       ),
     );
     await showProfile(tester, profiles);
+    expect(find.widgetWithText(TextField, 'Raison'), findsOneWidget);
 
     await tester.tap(find.text('Remove profile'));
     await tester.pumpAndSettle();
     expect(find.text('Remove your public profile?'), findsOneWidget);
+    expect(find.textContaining('Your handle stays yours'), findsOneWidget);
     await tester.tap(find.text('Remove profile').last);
     await tester.pumpAndSettle();
 
     expect(find.text('Profile removed.'), findsOneWidget);
-    expect(profiles.profile, isNull);
+    expect(profiles.profile?.handle, 'raisondetredev');
+    expect(profiles.profile?.displayName, '');
+    expect(find.text('@raisondetredev'), findsOneWidget);
+    // The form starts afresh from what is left.
+    expect(find.widgetWithText(TextField, 'Raison'), findsNothing);
+    expect(find.widgetWithText(TextField, 'Learning Japanese.'), findsNothing);
+    expect(
+      find.widgetWithText(TextField, 'https://halkyon.app'),
+      findsNothing,
+    );
+    // Nothing is left to remove.
+    expect(find.text('Remove profile'), findsNothing);
+  });
+
+  testWidgets('offers no removing while nothing is filled in: the handle '
+      'alone is private already', (tester) async {
+    await showProfile(
+      tester,
+      FakeProfileGateway(
+        profile: const PublicProfile(
+          handle: 'raisondetredev',
+          address: 'raisondetredev@halkyon.eu',
+        ),
+      ),
+    );
+
+    expect(find.text('@raisondetredev'), findsOneWidget);
+    expect(find.text('Remove profile'), findsNothing);
   });
 
   testWidgets('a saved profile takes a picture as its avatar, and gives it '

apps/learn/halkyon_learn_flutter/test/support/fake_profile_gateway.dart

@@ -145,14 +145,23 @@ class FakeProfileGateway({
   }
 
   @override
-  Future<void> remove() async {
+  Future<PublicProfile?> remove() async {
     if (fail case final error?) {
       throw error;
     }
-    if (profile?.handleFixed ?? false) {
+    final current = profile;
+    if (current == null) {
+      return null;
+    }
+    if (current.handleFixed) {
       throw ProfileRefused(ProfileProblem.published);
     }
-    profile = null;
+    // Private again, the handle kept (ADR 0020, D27).
+    return profile = PublicProfile(
+      handle: current.handle,
+      address: current.address,
+      pageUrl: current.pageUrl,
+    );
   }
 
   /// The links whose pages link back to the profile page.