feat(claude): Settings → Claude accounts registry list (T-482 part 2)

Completes the account settings surface with the global Accounts list under the
Claude category: each registered account shows a sign-in dot, name, and config
dir, with re-login and remove affordances plus an inline add-account field.

- Sign-in status: accountIsSignedIn, a read-only probe (a .credentials.json, or
  an oauthAccount marker in .claude.json; under-reports on macOS keychain).
- Add: registers ~/.claude-<name> and publishes a login action (T-485 opens the
  pane).
- Remove: registry-remove, guarded while a workspace is bound — matching the CLI
  `account remove`. --purge dir deletion stays on the CLI flag.

All management routes through the AccountRegistry + accountActionChannel, and
the list rebuilds live off the settings notifier. en/nl strings + widget/probe
tests added. Closes T-482.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

test/builtin/claude/account_registry_test.dart

@@ -138,6 +138,31 @@ void main() {
     });
   });
 
+  group('sign-in probe (T-482)', () {
+    test('true with a .credentials.json or an oauthAccount marker; false otherwise', () async {
+      final home = await Directory.systemTemp.createTemp('clide-signin-');
+      addTearDown(() => home.deleteSync(recursive: true));
+
+      // .credentials.json present → signed in.
+      final a = Directory('${home.path}/.claude-a')..createSync();
+      File('${a.path}/.credentials.json').writeAsStringSync('{}');
+      expect(accountIsSignedIn(a.path), isTrue);
+
+      // .claude.json with an oauthAccount marker → signed in.
+      final b = Directory('${home.path}/.claude-b')..createSync();
+      File('${b.path}/.claude.json').writeAsStringSync('{"oauthAccount": {"email": "x@y.z"}}');
+      expect(accountIsSignedIn(b.path), isTrue);
+
+      // .claude.json without the marker → not signed in.
+      final c = Directory('${home.path}/.claude-c')..createSync();
+      File('${c.path}/.claude.json').writeAsStringSync('{"theme": "dark"}');
+      expect(accountIsSignedIn(c.path), isFalse);
+
+      // No config dir at all → not signed in.
+      expect(accountIsSignedIn('${home.path}/.claude-missing'), isFalse);
+    });
+  });
+
   group('purge guard (T-480)', () {
     const home = '/home/u';
     test('accepts ~/.claude-* direct children only, rejects everything else', () {

test/builtin/claude/account_settings_control_test.dart

@@ -95,4 +95,64 @@ void main() {
     expect(published.single['action'], 'unset');
     expect(published.single['previous'], 'work');
   });
+
+  // The global registry list control (T-482 part 2).
+  Future<void> pumpList(WidgetTester tester) => tester.pumpWidget(
+    harness(
+      f,
+      const Align(
+        alignment: Alignment.center,
+        child: SizedBox(width: 460, child: ClaudeAccountsListControl()),
+      ),
+    ),
+  );
+
+  testWidgets('registry list: empty shows a hint + the add row', (tester) async {
+    await pumpList(tester);
+    await tester.pump();
+    expect(find.textContaining('No accounts registered'), findsOneWidget);
+    expect(find.text('Add account'), findsOneWidget);
+  });
+
+  testWidgets('registry list: renders each account name + dir', (tester) async {
+    final reg = AccountRegistry(f.services.settings);
+    await tester.runAsync(() => reg.registerAccount('work', '/home/u/.claude-work'));
+    await pumpList(tester);
+    await tester.pump();
+    expect(find.text('work'), findsOneWidget);
+    expect(find.text('/home/u/.claude-work'), findsOneWidget);
+  });
+
+  testWidgets('registry list: typing a name + Add registers it and publishes login', (tester) async {
+    final reg = AccountRegistry(f.services.settings);
+    final published = <Map<String, Object?>>[];
+    final sub = f.services.messages.subscribe(channel: accountActionChannel).listen((m) => published.add(m.data));
+    addTearDown(sub.cancel);
+
+    await pumpList(tester);
+    await tester.pump();
+    await tester.enterText(find.byType(EditableText), 'work');
+    await tester.tap(find.text('Add account'));
+    await tester.pump();
+    expect(reg.accountByName('work'), isNotNull);
+    expect(published.single['action'], 'login');
+    expect(published.single['name'], 'work');
+  });
+
+  testWidgets('registry list: remove deletes an unbound account; a bound one is guarded', (tester) async {
+    final reg = AccountRegistry(f.services.settings);
+    await tester.runAsync(() async {
+      await f.services.settings.setProjectDir(f.tempDir);
+      await reg.registerAccount('work', '/home/u/.claude-work');
+      await reg.registerAccount('personal', '/home/u/.claude-personal');
+      await reg.bindWorkspace(f.tempDir.path, 'work');
+    });
+
+    await pumpList(tester);
+    await tester.pump();
+    await tester.tap(find.bySemanticsLabel('Remove personal'));
+    await tester.pump();
+    expect(reg.accountByName('personal'), isNull);
+    expect(find.bySemanticsLabel(RegExp('bound to a workspace')), findsOneWidget, reason: 'the bound account guards its remove');
+  });
 }