refactor: implement trait-based DI for TdClient and fix stack overflow

Implement complete trait-based dependency injection pattern for TdClient
to enable testing with FakeTdClient mock. Fix critical stack overflow bugs
caused by infinite recursion in trait implementations.

Breaking Changes:
- App is now generic: App<T: TdClientTrait = TdClient>
- All UI and input handlers are generic over TdClientTrait
- TdClient methods now accessed through trait interface

New Files:
- src/tdlib/trait.rs: TdClientTrait definition with 40+ methods
- src/tdlib/client_impl.rs: TdClientTrait impl for TdClient
- tests/helpers/fake_tdclient_impl.rs: TdClientTrait impl for FakeTdClient

Critical Fixes:
- Fix stack overflow in send_message, edit_message, delete_messages
- Fix stack overflow in forward_messages, current_chat_messages
- Fix stack overflow in current_pinned_message
- All methods now call message_manager directly to avoid recursion

Testing:
- FakeTdClient supports configurable auth_state for auth screen tests
- Added pinned message support in FakeTdClient
- All 196+ tests passing (188 tests + 8 benchmarks)

Dependencies:
- Added async-trait = "0.1"

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/input/handlers/search.rs

@@ -1,16 +1,17 @@
 //! Search mode input handling (chat search and message search)
 
 use crate::app::App;
+use crate::tdlib::TdClientTrait;
 use crossterm::event::KeyEvent;
 
 /// Обрабатывает ввод в режиме поиска чатов
-pub async fn handle_chat_search_input(app: &mut App, key: KeyEvent) {
+pub async fn handle_chat_search_input<T: TdClientTrait>(app: &mut App<T>, key: KeyEvent) {
     // TODO: Implement chat search input handling
     let _ = (app, key);
 }
 
 /// Обрабатывает ввод в режиме поиска сообщений
-pub async fn handle_message_search_input(app: &mut App, key: KeyEvent) {
+pub async fn handle_message_search_input<T: TdClientTrait>(app: &mut App<T>, key: KeyEvent) {
     // TODO: Implement message search input handling
     let _ = (app, key);
 }