refactor(#271,#272,#273): reorder settings categories

- #271 Node Settings moves to the top
- #272 Blocked moves below Contacts
- #273 App Settings moves above Device Info

New order: Node Settings, Radio Settings, Radio Stats, Privacy, Contacts,
Blocked, Messages, App Settings, Device Info, Observer, Actions, Debug.

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

lib/screens/settings_screen.dart

@@ -87,6 +87,11 @@ class _SettingsScreenState extends State<SettingsScreen> {
       ),
     );
     return [
+      SettingsCategory(
+        icon: Icons.badge_outlined,
+        title: l10n.settings_nodeSettings,
+        builder: _identityPane,
+      ),
       SettingsCategory(
         icon: Icons.settings_input_antenna,
         title: l10n.settings_radioSettings,
@@ -99,35 +104,36 @@ class _SettingsScreenState extends State<SettingsScreen> {
         subtitle: l10n.radioStats_settingsSubtitle,
         builder: _radioStatsPane,
       ),
-      SettingsCategory(
-        icon: Icons.badge_outlined,
-        title: l10n.settings_nodeSettings,
-        builder: _identityPane,
-      ),
       SettingsCategory(
         icon: Icons.shield_outlined,
         title: l10n.settings_privacy,
         subtitle: l10n.settings_privacySubtitle,
         builder: _privacyPane,
       ),
-      SettingsCategory(
-        icon: Icons.block,
-        title: l10n.block_settingsTitle,
-        subtitle: l10n.block_settingsSubtitle,
-        builder: _blockedPane,
-      ),
       SettingsCategory(
         icon: Icons.contacts_outlined,
         title: l10n.contacts_title,
         subtitle: l10n.settings_contactSettingsSubtitle,
         builder: _contactsPane,
       ),
+      SettingsCategory(
+        icon: Icons.block,
+        title: l10n.block_settingsTitle,
+        subtitle: l10n.block_settingsSubtitle,
+        builder: _blockedPane,
+      ),
       SettingsCategory(
         icon: Icons.sms_outlined,
         title: l10n.settings_messageSettings,
         subtitle: l10n.settings_messageSettingsSubtitle,
         builder: _messageSettingsPane,
       ),
+      SettingsCategory(
+        icon: Icons.tune,
+        title: l10n.settings_appSettings,
+        subtitle: l10n.settings_appSettingsSubtitle,
+        builder: _appPane,
+      ),
       SettingsCategory(
         icon: Icons.info_outline,
         title: l10n.settings_deviceInfo,
@@ -140,12 +146,6 @@ class _SettingsScreenState extends State<SettingsScreen> {
           subtitle: 'WiFi · MQTT brokers · display',
           builder: _observerPane,
         ),
-      SettingsCategory(
-        icon: Icons.tune,
-        title: l10n.settings_appSettings,
-        subtitle: l10n.settings_appSettingsSubtitle,
-        builder: _appPane,
-      ),
       SettingsCategory(
         icon: Icons.bolt_outlined,
         title: l10n.settings_actions,