feat(settings): About section with version + force update check

Adds an About card to Settings that shows the installed version
(version+build from PackageInfo), the latest known version from
clientUpdateProvider, and a "Check for updates" button that
invalidates the provider to force a fresh poll. When an update is
available, surfaces an Install CTA that reuses the same installer
flow as the top banner.

The existing banner (shouldShowUpdateBannerProvider) is unaffected
— it gates on per-version dismissal, while the About section
always reflects the current provider state regardless of dismissal.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

flutter_client/lib/settings/about_section.dart

@@ -0,0 +1,227 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:package_info_plus/package_info_plus.dart';
+
+import '../theme/theme_extension.dart';
+import '../update/client_update_provider.dart';
+import '../update/update_info.dart';
+
+final _packageInfoProvider = FutureProvider<PackageInfo>((_) {
+  return PackageInfo.fromPlatform();
+});
+
+class AboutSection extends ConsumerStatefulWidget {
+  const AboutSection({super.key});
+
+  @override
+  ConsumerState<AboutSection> createState() => _AboutSectionState();
+}
+
+enum _InstallStage { idle, downloading, error }
+
+class _AboutSectionState extends ConsumerState<AboutSection> {
+  DateTime? _lastChecked;
+  bool _checking = false;
+
+  _InstallStage _installStage = _InstallStage.idle;
+  double _installProgress = 0;
+  String? _installError;
+
+  Future<void> _checkNow() async {
+    setState(() => _checking = true);
+    ref.invalidate(clientUpdateProvider);
+    try {
+      await ref.read(clientUpdateProvider.future);
+    } finally {
+      if (mounted) {
+        setState(() {
+          _checking = false;
+          _lastChecked = DateTime.now();
+        });
+      }
+    }
+  }
+
+  Future<void> _install(UpdateInfo info) async {
+    setState(() {
+      _installStage = _InstallStage.downloading;
+      _installProgress = 0;
+      _installError = null;
+    });
+    try {
+      final installer = await ref.read(updateInstallerProvider.future);
+      final path = await installer.download(
+        info.apkUrl,
+        onProgress: (p) {
+          if (mounted) setState(() => _installProgress = p);
+        },
+      );
+      await installer.install(path);
+    } catch (e) {
+      if (!mounted) return;
+      setState(() {
+        _installStage = _InstallStage.error;
+        _installError = '$e';
+      });
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
+    final pkg = ref.watch(_packageInfoProvider);
+    final update = ref.watch(clientUpdateProvider);
+
+    final installed = pkg.value == null
+        ? '…'
+        : '${pkg.value!.version}+${pkg.value!.buildNumber}';
+
+    final UpdateInfo? available = update.value;
+    final hasUpdate = available != null;
+
+    return Column(crossAxisAlignment: CrossAxisAlignment.start, children: [
+      const Padding(
+        padding: EdgeInsets.fromLTRB(16, 4, 16, 8),
+        child: _SectionHeader('About'),
+      ),
+      Padding(
+        padding: const EdgeInsets.fromLTRB(16, 0, 16, 4),
+        child: Row(
+          children: [
+            Icon(Icons.info_outline, color: fs.parchment, size: 18),
+            const SizedBox(width: 8),
+            Text('Installed version',
+                style: TextStyle(color: fs.parchment, fontSize: 14)),
+            const Spacer(),
+            Text(installed,
+                style: TextStyle(
+                    color: fs.ash,
+                    fontSize: 13,
+                    fontFamily: 'JetBrainsMono')),
+          ],
+        ),
+      ),
+      Padding(
+        padding: const EdgeInsets.fromLTRB(16, 4, 16, 4),
+        child: Row(
+          children: [
+            Icon(Icons.cloud_outlined, color: fs.parchment, size: 18),
+            const SizedBox(width: 8),
+            Text('Latest version',
+                style: TextStyle(color: fs.parchment, fontSize: 14)),
+            const Spacer(),
+            Text(
+              hasUpdate ? available.version : _statusFor(update, installed),
+              style: TextStyle(
+                  color: hasUpdate ? fs.accent : fs.ash,
+                  fontSize: 13,
+                  fontFamily: 'JetBrainsMono'),
+            ),
+          ],
+        ),
+      ),
+      if (_lastChecked != null)
+        Padding(
+          padding: const EdgeInsets.fromLTRB(16, 4, 16, 0),
+          child: Text(
+            'Last checked ${_formatTime(_lastChecked!)}',
+            style: TextStyle(color: fs.ash, fontSize: 11),
+          ),
+        ),
+      Padding(
+        padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
+        child: Row(
+          children: [
+            FilledButton.icon(
+              key: const Key('about_check_for_updates'),
+              onPressed: _checking ? null : _checkNow,
+              style: FilledButton.styleFrom(
+                backgroundColor: fs.accent,
+                foregroundColor: fs.parchment,
+              ),
+              icon: _checking
+                  ? SizedBox(
+                      width: 14,
+                      height: 14,
+                      child: CircularProgressIndicator(
+                        strokeWidth: 2,
+                        valueColor: AlwaysStoppedAnimation(fs.parchment),
+                      ),
+                    )
+                  : const Icon(Icons.refresh, size: 18),
+              label: Text(_checking ? 'Checking…' : 'Check for updates'),
+            ),
+            if (hasUpdate) ...[
+              const SizedBox(width: 12),
+              FilledButton.icon(
+                key: const Key('about_install_update'),
+                onPressed: _installStage == _InstallStage.downloading
+                    ? null
+                    : () => _install(available),
+                style: FilledButton.styleFrom(
+                  backgroundColor: fs.moss,
+                  foregroundColor: fs.parchment,
+                ),
+                icon: _installStage == _InstallStage.downloading
+                    ? SizedBox(
+                        width: 14,
+                        height: 14,
+                        child: CircularProgressIndicator(
+                          strokeWidth: 2,
+                          value: _installProgress > 0 ? _installProgress : null,
+                          valueColor: AlwaysStoppedAnimation(fs.parchment),
+                        ),
+                      )
+                    : const Icon(Icons.system_update, size: 18),
+                label: Text(
+                  _installStage == _InstallStage.downloading
+                      ? 'Downloading…'
+                      : _installStage == _InstallStage.error
+                          ? 'Retry install'
+                          : 'Install ${available.version}',
+                ),
+              ),
+            ],
+          ],
+        ),
+      ),
+      if (_installStage == _InstallStage.error && _installError != null)
+        Padding(
+          padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
+          child: Text(_installError!,
+              style: TextStyle(color: fs.error, fontSize: 12),
+              maxLines: 2,
+              overflow: TextOverflow.ellipsis),
+        ),
+    ]);
+  }
+
+  String _statusFor(AsyncValue<UpdateInfo?> update, String installed) {
+    if (update.isLoading) return 'Checking…';
+    if (update.hasError) return 'Check failed';
+    return 'Up to date';
+  }
+
+  String _formatTime(DateTime t) {
+    final h = t.hour.toString().padLeft(2, '0');
+    final m = t.minute.toString().padLeft(2, '0');
+    return '$h:$m';
+  }
+}
+
+class _SectionHeader extends StatelessWidget {
+  const _SectionHeader(this.label);
+  final String label;
+  @override
+  Widget build(BuildContext context) {
+    final fs = Theme.of(context).extension<FabledSwordTheme>()!;
+    return Text(
+      label,
+      style: TextStyle(
+        color: fs.parchment,
+        fontSize: 16,
+        fontWeight: FontWeight.w500,
+      ),
+    );
+  }
+}

flutter_client/lib/settings/settings_screen.dart

@@ -9,6 +9,7 @@ import '../library/library_providers.dart' show dioProvider;
 import '../models/my_profile.dart';
 import '../shared/widgets/main_app_bar_actions.dart';
 import '../theme/theme_extension.dart';
+import 'about_section.dart';
 import 'storage_section.dart';
 import '../theme/theme_mode_provider.dart';
 
@@ -56,6 +57,8 @@ class SettingsScreen extends ConsumerWidget {
           _PasswordSection(),
           _Divider(),
           _ListenBrainzSection(),
+          _Divider(),
+          AboutSection(),
           _AdminSection(),
           SizedBox(height: 96),
         ],