feat(app): группированный сайдбар навигации на широком breakpoint

NavSidebar (>=1200): пункты меню сгруппированы под капс-заголовками,
у активного пункта левая акцентная полоска, у «Здоровье» — счётчик
замечаний качества данных из dataQualityProvider, внизу закреплён
профиль (аватар-инициал + email из meProvider). Список направлений
вынесен в nav_destinations.dart — общий для app_shell.dart и
nav_sidebar.dart. На 600–1200 остаётся свёрнутый NavigationRail: в
иконку-без-подписи заголовки групп и профиль всё равно не помещаются.

NavSidebar смонтирован всё время сессии и держит dataQualityProvider
и meProvider живыми — раньше эти запросы уходили только при открытии
Обзора/Здоровья/Настроек.

app/lib/features/shell/app_shell.dart

@@ -1,55 +1,8 @@
 import 'package:flutter/material.dart';
 import 'package:go_router/go_router.dart';
 
-class _Destination {
-  const _Destination(this.path, this.icon, this.selectedIcon, this.label,
-      {this.alsoMatches = const [], this.primary = false});
-  final String path;
-  final IconData icon;
-  final IconData selectedIcon;
-  final String label;
-
-  /// Extra route prefixes that belong to this destination but do not start with [path] —
-  /// `/instruments/pending` is reached from Импорт and must keep it highlighted, and the
-  /// four phase-4 screens are reached from Аналитика the same way.
-  final List<String> alsoMatches;
-
-  /// Shown directly in the bottom bar on a phone. Everything else moves behind «Ещё».
-  final bool primary;
-
-  /// The longest prefix of [location] this destination claims, or -1 for no match.
-  int matchLength(String location) {
-    var best = -1;
-    for (final p in [path, ...alsoMatches]) {
-      final hit = p == '/' ? location == '/' : location.startsWith(p);
-      if (hit && p.length > best) best = p.length;
-    }
-    return best;
-  }
-}
-
-const _destinations = [
-  _Destination('/', Icons.dashboard_outlined, Icons.dashboard, 'Обзор', primary: true),
-  _Destination('/accounts', Icons.account_balance_outlined, Icons.account_balance, 'Счета',
-      primary: true),
-  _Destination('/portfolio', Icons.pie_chart_outline, Icons.pie_chart, 'Портфель',
-      primary: true),
-  // One entry for the four phase-4 screens. They keep their own top-level routes from the
-  // contract and stay deep-linkable; the hub at `/analytics` is what the bottom bar and the
-  // rail point at, and `alsoMatches` keeps it highlighted while you are inside any of them.
-  _Destination('/analytics', Icons.insights_outlined, Icons.insights, 'Аналитика',
-      alsoMatches: ['/income', '/rebalance', '/goals', '/tax'], primary: true),
-  _Destination('/events', Icons.event_note_outlined, Icons.event_note, 'События'),
-  _Destination('/imports', Icons.upload_file_outlined, Icons.upload_file, 'Импорт',
-      alsoMatches: ['/instruments/pending']),
-  _Destination('/cashflow', Icons.swap_horiz_outlined, Icons.swap_horiz, 'Потоки'),
-  _Destination('/categories', Icons.category_outlined, Icons.category, 'Категории'),
-  _Destination(
-      '/transactions', Icons.receipt_long_outlined, Icons.receipt_long, 'Операции'),
-  _Destination('/rules', Icons.rule_folder_outlined, Icons.rule_folder, 'Правила'),
-  _Destination('/health', Icons.monitor_heart_outlined, Icons.monitor_heart, 'Здоровье'),
-  _Destination('/settings', Icons.settings_outlined, Icons.settings, 'Настройки'),
-];
+import 'nav_destinations.dart';
+import 'nav_sidebar.dart';
 
 /// Breakpoints per the plan: bottom bar under 600, collapsed rail 600–1200,
 /// extended rail at 1200 and above.
@@ -57,12 +10,12 @@ const _narrowBreakpoint = 600.0;
 const _wideBreakpoint = 1200.0;
 
 /// Adaptive navigation shell around the current route: a bottom
-/// [NavigationBar] on narrow surfaces, a [NavigationRail] (collapsed or
-/// extended) otherwise.
+/// [NavigationBar] on narrow surfaces, a collapsed [NavigationRail] on medium
+/// ones, and the grouped [NavSidebar] on wide ones.
 ///
-/// The rail shows every destination. The bottom bar shows the four primary ones plus
-/// «Ещё», which opens the rest in a sheet: twelve destinations in a phone-width bar would
-/// leave about 30 px per label, which is not navigation but decoration.
+/// The rail and the sidebar show every destination. The bottom bar shows the four primary
+/// ones plus «Ещё», which opens the rest in a sheet: twelve destinations in a phone-width
+/// bar would leave about 30 px per label, which is not navigation but decoration.
 class AppShell extends StatelessWidget {
   const AppShell({required this.location, required this.child, super.key});
 
@@ -73,8 +26,8 @@ class AppShell extends StatelessWidget {
     // longest prefix wins, so /portfolio/instrument/311 keeps Портфель selected
     var best = -1;
     var bestLength = -1;
-    for (var i = 0; i < _destinations.length; i++) {
-      final length = _destinations[i].matchLength(location);
+    for (var i = 0; i < navDestinations.length; i++) {
+      final length = navDestinations[i].matchLength(location);
       if (length > bestLength) {
         best = i;
         bestLength = length;
@@ -84,7 +37,7 @@ class AppShell extends StatelessWidget {
   }
 
   void _onSelect(BuildContext context, int index) {
-    if (index != _selectedIndex) context.go(_destinations[index].path);
+    if (index != _selectedIndex) context.go(navDestinations[index].path);
   }
 
   @override
@@ -92,8 +45,8 @@ class AppShell extends StatelessWidget {
     final width = MediaQuery.sizeOf(context).width;
 
     if (width < _narrowBreakpoint) {
-      final primary = _destinations.where((d) => d.primary).toList();
-      final selected = _destinations[_selectedIndex];
+      final primary = navDestinations.where((d) => d.primary).toList();
+      final selected = navDestinations[_selectedIndex];
       final primaryIndex = primary.indexOf(selected);
 
       return Scaffold(
@@ -106,7 +59,7 @@ class AppShell extends StatelessWidget {
             if (i >= primary.length) {
               _showMore(context, selected);
             } else {
-              final target = _destinations.indexOf(primary[i]);
+              final target = navDestinations.indexOf(primary[i]);
               _onSelect(context, target);
             }
           },
@@ -131,21 +84,22 @@ class AppShell extends StatelessWidget {
     return Scaffold(
       body: Row(
         children: [
-          NavigationRail(
-            extended: extended,
-            minExtendedWidth: 220,
-            selectedIndex: _selectedIndex,
-            onDestinationSelected: (i) => _onSelect(context, i),
-            labelType: extended ? NavigationRailLabelType.none : NavigationRailLabelType.selected,
-            destinations: [
-              for (final d in _destinations)
-                NavigationRailDestination(
-                  icon: Icon(d.icon),
-                  selectedIcon: Icon(d.selectedIcon),
-                  label: Text(d.label),
-                ),
-            ],
-          ),
+          if (extended)
+            NavSidebar(selectedIndex: _selectedIndex, onSelect: (i) => _onSelect(context, i))
+          else
+            NavigationRail(
+              selectedIndex: _selectedIndex,
+              onDestinationSelected: (i) => _onSelect(context, i),
+              labelType: NavigationRailLabelType.selected,
+              destinations: [
+                for (final d in navDestinations)
+                  NavigationRailDestination(
+                    icon: Icon(d.icon),
+                    selectedIcon: Icon(d.selectedIcon),
+                    label: Text(d.label),
+                  ),
+              ],
+            ),
           const VerticalDivider(width: 1),
           Expanded(child: SafeArea(child: child)),
         ],
@@ -155,7 +109,7 @@ class AppShell extends StatelessWidget {
 
   /// The non-primary destinations, as a sheet. The currently open one is ticked, so «Ещё»
   /// still answers "where am I".
-  void _showMore(BuildContext context, _Destination current) {
+  void _showMore(BuildContext context, NavDestination current) {
     showModalBottomSheet<void>(
       context: context,
       showDragHandle: true,
@@ -163,7 +117,7 @@ class AppShell extends StatelessWidget {
         child: ListView(
           shrinkWrap: true,
           children: [
-            for (final d in _destinations.where((d) => !d.primary))
+            for (final d in navDestinations.where((d) => !d.primary))
               ListTile(
                 leading: Icon(d == current ? d.selectedIcon : d.icon),
                 title: Text(d.label),