feat: implement Iteration 6 — profile screen

Add ProfileService (GET/PUT /profile), ProfileNotifier provider,
and full ProfileScreen with body-params, goal/activity, daily-calories
sections and logout confirmation. EditProfileSheet lets user update
name, height, weight, age, gender, goal and activity; backend
auto-recalculates daily_calories via Mifflin-St Jeor.
HomeScreen greeting now shows the user's real name from profileProvider.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/lib/features/home/home_screen.dart

@@ -4,6 +4,7 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
 
 import '../../shared/models/home_summary.dart';
+import '../profile/profile_provider.dart';
 import 'home_provider.dart';
 
 class HomeScreen extends ConsumerWidget {
@@ -12,6 +13,7 @@ class HomeScreen extends ConsumerWidget {
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final state = ref.watch(homeProvider);
+    final userName = ref.watch(profileProvider).valueOrNull?.name;
 
     return Scaffold(
       body: state.when(
@@ -26,7 +28,7 @@ class HomeScreen extends ConsumerWidget {
           onRefresh: () => ref.read(homeProvider.notifier).load(),
           child: CustomScrollView(
             slivers: [
-              _AppBar(summary: summary),
+              _AppBar(summary: summary, userName: userName),
               SliverPadding(
                 padding: const EdgeInsets.fromLTRB(16, 0, 16, 100),
                 sliver: SliverList(
@@ -62,15 +64,22 @@ class HomeScreen extends ConsumerWidget {
 
 class _AppBar extends StatelessWidget {
   final HomeSummary summary;
-  const _AppBar({required this.summary});
+  final String? userName;
+  const _AppBar({required this.summary, this.userName});
 
-  String get _greeting {
+  String get _greetingBase {
     final hour = DateTime.now().hour;
     if (hour < 12) return 'Доброе утро';
     if (hour < 18) return 'Добрый день';
     return 'Добрый вечер';
   }
 
+  String get _greeting {
+    final name = userName;
+    if (name != null && name.isNotEmpty) return '$_greetingBase, $name!';
+    return _greetingBase;
+  }
+
   String get _dateLabel {
     final now = DateTime.now();
     const months = [