feat(#18): promote Radio Stats to top-level + rename Contact Settings to Contacts

Flatten two more redundant layers in the settings IA. Radio Stats: extract CompanionRadioStatsScreen's body into an embeddable CompanionRadioStatsBody (carrying the 1s-polling acquire/release lifecycle), add a top-level Radio Stats category that renders it directly, and remove the nested Radio Stats tile from the Radio Settings pane (the screen is kept; still pushed from radio_stats_entry.dart). Rename the Contact Settings category to Contacts (reusing contacts_title) with a contacts icon; rename _messagesContactsPane to _contactsPane.

Also fixes a pre-existing chart-freeze surfaced by review: _NoiseChartPainter compared only sample-list length, so the noise chart stopped repainting once the 120-sample buffer filled. Now compares contents via listEquals.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/screens/companion_radio_stats_screen.dart

@@ -1,18 +1,37 @@
+import 'package:flutter/foundation.dart' show listEquals;
 import 'package:flutter/material.dart';
 import 'package:meshcore_open/connector/meshcore_connector.dart';
 import 'package:meshcore_open/models/companion_radio_stats.dart';
 import 'package:meshcore_open/l10n/l10n.dart';
 import 'package:provider/provider.dart';
 
-class CompanionRadioStatsScreen extends StatefulWidget {
+class CompanionRadioStatsScreen extends StatelessWidget {
   const CompanionRadioStatsScreen({super.key});
 
   @override
-  State<CompanionRadioStatsScreen> createState() =>
-      _CompanionRadioStatsScreenState();
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(context.l10n.radioStats_screenTitle),
+        centerTitle: true,
+      ),
+      body: const CompanionRadioStatsBody(),
+    );
+  }
 }
 
-class _CompanionRadioStatsScreenState extends State<CompanionRadioStatsScreen> {
+/// Embeddable Radio Stats content (no Scaffold) — used by both
+/// [CompanionRadioStatsScreen] and the settings shell's Radio Stats pane.
+/// Acquires 1 s radio-stats polling while mounted and releases it on dispose.
+class CompanionRadioStatsBody extends StatefulWidget {
+  const CompanionRadioStatsBody({super.key});
+
+  @override
+  State<CompanionRadioStatsBody> createState() =>
+      _CompanionRadioStatsBodyState();
+}
+
+class _CompanionRadioStatsBodyState extends State<CompanionRadioStatsBody> {
   final List<double> _noiseHistory = [];
   static const int _maxSamples = 120;
   MeshCoreConnector? _connector;
@@ -52,16 +71,9 @@ class _CompanionRadioStatsScreenState extends State<CompanionRadioStatsScreen> {
   @override
   Widget build(BuildContext context) {
     final l10n = context.l10n;
-    return Scaffold(
-      appBar: AppBar(
-        title: Text(l10n.radioStats_screenTitle),
-        centerTitle: true,
-      ),
-      body: Selector<MeshCoreConnector, ({bool connected, bool supported})>(
-        selector: (_, c) => (
-          connected: c.isConnected,
-          supported: c.supportsCompanionRadioStats,
-        ),
+    return Selector<MeshCoreConnector, ({bool connected, bool supported})>(
+      selector: (_, c) =>
+          (connected: c.isConnected, supported: c.supportsCompanionRadioStats),
       builder: (context, state, _) {
         if (!state.connected) {
           return Center(child: Text(l10n.radioStats_notConnected));
@@ -95,9 +107,7 @@ class _CompanionRadioStatsScreenState extends State<CompanionRadioStatsScreen> {
                   const SizedBox(height: 4),
                   Text(l10n.radioStats_lastRssi(stats.lastRssiDbm)),
                   Text(
-                      l10n.radioStats_lastSnr(
-                        stats.lastSnrDb.toStringAsFixed(1),
-                      ),
+                    l10n.radioStats_lastSnr(stats.lastSnrDb.toStringAsFixed(1)),
                   ),
                   Text(l10n.radioStats_txAir(stats.txAirSecs)),
                   Text(l10n.radioStats_rxAir(stats.rxAirSecs)),
@@ -119,16 +129,13 @@ class _CompanionRadioStatsScreenState extends State<CompanionRadioStatsScreen> {
                 const SizedBox(height: 8),
                 Text(
                   l10n.radioStats_chartCaption,
-                    style: tt.bodySmall?.copyWith(
-                      color: scheme.onSurfaceVariant,
-                    ),
+                  style: tt.bodySmall?.copyWith(color: scheme.onSurfaceVariant),
                 ),
               ],
             );
           },
         );
       },
-      ),
     );
   }
 }
@@ -233,8 +240,8 @@ class _NoiseChartPainter extends CustomPainter {
 
   @override
   bool shouldRepaint(covariant _NoiseChartPainter oldDelegate) {
-    return oldDelegate.samples.length != samples.length ||
-        oldDelegate.colorScheme != colorScheme;
+    return oldDelegate.colorScheme != colorScheme ||
+        !listEquals(oldDelegate.samples, samples);
   }
 
   TextPainter _yAxisLabel(double v) {

lib/screens/settings_screen.dart

@@ -16,7 +16,7 @@ import 'settings/app_settings_view.dart';
 import 'settings/message_settings_view.dart';
 import 'app_debug_log_screen.dart';
 import 'ble_debug_log_screen.dart';
-import '../widgets/radio_stats_entry.dart';
+import 'companion_radio_stats_screen.dart';
 import '../widgets/sync_progress_overlay.dart';
 
 /// Convert device coding-rate value (1-4 on some firmware, 5-8 on others)
@@ -78,6 +78,12 @@ class _SettingsScreenState extends State<SettingsScreen> {
         subtitle: l10n.settings_radioSettingsSubtitle,
         builder: _radioRangePane,
       ),
+      SettingsCategory(
+        icon: Icons.sensors_outlined,
+        title: l10n.radioStats_settingsTile,
+        subtitle: l10n.radioStats_settingsSubtitle,
+        builder: _radioStatsPane,
+      ),
       SettingsCategory(
         icon: Icons.badge_outlined,
         title: l10n.settings_nodeSettings,
@@ -90,10 +96,10 @@ class _SettingsScreenState extends State<SettingsScreen> {
         builder: _privacyPane,
       ),
       SettingsCategory(
-        icon: Icons.forum_outlined,
-        title: l10n.settings_contactSettings,
+        icon: Icons.contacts_outlined,
+        title: l10n.contacts_title,
         subtitle: l10n.settings_contactSettingsSubtitle,
-        builder: _messagesContactsPane,
+        builder: _contactsPane,
       ),
       SettingsCategory(
         icon: Icons.sms_outlined,
@@ -144,17 +150,6 @@ class _SettingsScreenState extends State<SettingsScreen> {
               ),
               const Divider(height: 1),
               _PathHashSizeTile(connector: connector),
-              const Divider(height: 1),
-              ListTile(
-                leading: const Icon(Icons.sensors_outlined),
-                title: Text(l10n.radioStats_settingsTile),
-                subtitle: Text(l10n.radioStats_settingsSubtitle),
-                trailing: const Icon(Icons.chevron_right),
-                enabled:
-                    connector.isConnected &&
-                    connector.supportsCompanionRadioStats,
-                onTap: () => pushCompanionRadioStatsScreen(context),
-              ),
             ],
           ),
         ),
@@ -162,6 +157,9 @@ class _SettingsScreenState extends State<SettingsScreen> {
     );
   }
 
+  Widget _radioStatsPane(BuildContext context) =>
+      const CompanionRadioStatsBody();
+
   Widget _identityPane(BuildContext context) {
     final l10n = context.l10n;
     final connector = context.watch<MeshCoreConnector>();
@@ -237,7 +235,7 @@ class _SettingsScreenState extends State<SettingsScreen> {
     );
   }
 
-  Widget _messagesContactsPane(BuildContext context) {
+  Widget _contactsPane(BuildContext context) {
     final l10n = context.l10n;
     final connector = context.watch<MeshCoreConnector>();
     return ListView(