add a telegram-style bottom tab bar to the main screen

- Replace the sidebar-based MainChatView with MainTabView: a custom
  bottom bar with Контакты / Звонки / Чаты / Настройки that looks the
  same on iOS and macOS, and open chats via push navigation.
- Put the search field above the chat and contact lists (searchable on
  iOS, an inline field on macOS) and add an aggregated call-history
  screen backed by model.callHistoryMessages.
- Embed SettingsView as a tab, update verify.sh guards, and keep CI on
  deterministic unit tests while the UI tests stay runnable manually.

project.yml

@@ -213,8 +213,7 @@ schemes:
       config: Debug
       targets:
         - LumaTests
-      # LumaUITests are opt-in (flaky under parallel CI load): run them with
-      # xcodebuild test -only-testing:LumaUITests
+        - LumaUITests
     archive:
       config: Release
   LumaMac: