feat(flutter): adopt MainAppBarActions in Home + Library

HomeScreen drops its 5 ad-hoc IconButton actions in favour of the shared
widget. LibraryScreen gains an actions row it didn't have before. Both
now consistent.

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

flutter_client/lib/library/home_screen.dart

@@ -1,7 +1,6 @@
 import 'package:dio/dio.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
-import 'package:go_router/go_router.dart';
 
 import '../api/errors.dart';
 import '../models/album.dart';
@@ -9,6 +8,7 @@ import '../models/artist.dart';
 import '../models/track.dart';
 import '../player/player_provider.dart';
 import '../shared/widgets/connection_error_banner.dart';
+import '../shared/widgets/main_app_bar_actions.dart';
 import '../theme/theme_extension.dart';
 import 'library_providers.dart';
 import 'widgets/album_card.dart';
@@ -28,33 +28,7 @@ class HomeScreen extends ConsumerWidget {
         backgroundColor: fs.obsidian,
         elevation: 0,
         title: Text('Minstrel', style: TextStyle(color: fs.parchment)),
-        actions: [
-          IconButton(
-            icon: Icon(Icons.library_music, color: fs.parchment),
-            tooltip: 'Library',
-            onPressed: () => context.push('/library'),
-          ),
-          IconButton(
-            icon: Icon(Icons.queue_music, color: fs.parchment),
-            tooltip: 'Playlists',
-            onPressed: () => context.push('/playlists'),
-          ),
-          IconButton(
-            icon: Icon(Icons.search, color: fs.parchment),
-            tooltip: 'Search',
-            onPressed: () => context.push('/search'),
-          ),
-          IconButton(
-            icon: Icon(Icons.explore, color: fs.parchment),
-            tooltip: 'Discover',
-            onPressed: () => context.push('/discover'),
-          ),
-          IconButton(
-            icon: Icon(Icons.settings, color: fs.parchment),
-            tooltip: 'Settings',
-            onPressed: () => context.push('/settings'),
-          ),
-        ],
+        actions: const [MainAppBarActions(currentRoute: '/home')],
       ),
       body: SafeArea(
         child: ref.watch(homeProvider).when(

flutter_client/lib/library/library_screen.dart

@@ -15,6 +15,7 @@ import '../models/page.dart' as wire;
 import '../models/quarantine_mine.dart';
 import '../models/track.dart';
 import '../player/player_provider.dart';
+import '../shared/widgets/main_app_bar_actions.dart';
 import '../theme/theme_extension.dart';
 import 'widgets/album_card.dart';
 import 'widgets/artist_card.dart';
@@ -90,6 +91,7 @@ class _LibraryScreenState extends ConsumerState<LibraryScreen>
         backgroundColor: fs.obsidian,
         elevation: 0,
         title: Text('Library', style: TextStyle(color: fs.parchment)),
+        actions: const [MainAppBarActions(currentRoute: '/library')],
         bottom: TabBar(
           controller: _ctrl,
           isScrollable: true,