feat: implement cross-platform features and UI integration

- iOS: Add BackgroundSyncService, SyncScheduler, SyncWorker, BookmarkViewModel, FeedViewModel
- iOS: Add BackgroundSyncService, SyncScheduler, SyncWorker services
- Linux: Add settings-store.vala, State.vala signals, view widgets (FeedList, FeedDetail, AddFeed, Search, Settings, Bookmark)
- Linux: Add bookmark-store.vala, bookmark vala model, search-service.vala
- Android: Add NotificationService, NotificationManager, NotificationPreferencesStore
- Android: Add BookmarkDao, BookmarkRepository, SettingsStore
- Add unit tests for iOS, Android, Linux
- Add integration tests
- Add performance benchmarks
- Update tasks and documentation

Co-Authored-By: Paperclip <noreply@paperclip.ing>

linux/meson.build

@@ -18,6 +18,7 @@ sqlite_dep = dependency('sqlite3', version: '>= 3.0')
 gobject_dep = dependency('gobject-2.0', version: '>= 2.58')
 xml_dep = dependency('libxml-2.0', version: '>= 2.0')
 soup_dep = dependency('libsoup-3.0', version: '>= 3.0')
+gtk_dep = dependency('gtk4', version: '>= 4.0')
 
 # Source files
 models = files(
@@ -28,6 +29,7 @@ models = files(
   'src/models/search-filters.vala',
   'src/models/notification-preferences.vala',
   'src/models/reading-preferences.vala',
+  'src/models/bookmark.vala',
 )
 
 # Database files
@@ -37,6 +39,18 @@ database = files(
   'src/database/subscription-store.vala',
   'src/database/feed-item-store.vala',
   'src/database/search-history-store.vala',
+  'src/database/bookmark-store.vala',
+)
+
+# Repository files
+repositories = files(
+  'src/repository/bookmark-repository.vala',
+  'src/repository/bookmark-repository-impl.vala',
+)
+
+# Service files
+services = files(
+  'src/service/search-service.vala',
 )
 
 # Parser files
@@ -70,6 +84,14 @@ database_lib = library('rssuper-database', database,
   vala_args: ['--vapidir', 'src/database', '--pkg', 'sqlite3']
 )
 
+# Repository library
+repository_lib = library('rssuper-repositories', repositories,
+  dependencies: [glib_dep, gio_dep, json_dep, sqlite_dep],
+  link_with: [models_lib, database_lib],
+  install: false,
+  vala_args: ['--vapidir', 'src/repository']
+)
+
 # Parser library
 parser_lib = library('rssuper-parser', parser,
   dependencies: [glib_dep, gio_dep, json_dep, xml_dep],
@@ -113,7 +135,27 @@ fetcher_test_exe = executable('feed-fetcher-tests',
   install: false
 )
 
+# Notification service test executable
+notification_service_test_exe = executable('notification-service-tests',
+  'src/tests/notification-service-tests.vala',
+  dependencies: [glib_dep, gio_dep, json_dep, gobject_dep],
+  link_with: [models_lib],
+  vala_args: ['--vapidir', '.', '--pkg', 'gio-2.0'],
+  install: false
+)
+
+# Notification manager test executable
+notification_manager_test_exe = executable('notification-manager-tests',
+  'src/tests/notification-manager-tests.vala',
+  dependencies: [glib_dep, gio_dep, json_dep, gobject_dep, gtk_dep],
+  link_with: [models_lib],
+  vala_args: ['--vapidir', '.', '--pkg', 'gio-2.0', '--pkg', 'gtk4'],
+  install: false
+)
+
 # Test definitions
 test('database tests', test_exe)
 test('parser tests', parser_test_exe)
 test('feed fetcher tests', fetcher_test_exe)
+test('notification service tests', notification_service_test_exe)
+test('notification manager tests', notification_manager_test_exe)