fix: mark incoming messages as read when opening chat and load all history

Fixes two critical bugs:
1. Unread badge not clearing when opening chat - incoming messages weren't marked as viewed
2. Only last 2-3 messages loaded instead of full history due to incorrect break condition

Changes:
- Add incoming message IDs to pending_view_messages queue on chat open
- Remove premature break in get_chat_history() that stopped after 2 messages
- Add FakeTdClient.pending_view_messages field for testing
- Implement process_pending_view_messages() in FakeTdClient

Tests added:
- test_incoming_message_shows_unread_badge: verify "(1)" appears for unread
- test_opening_chat_clears_unread_badge: verify badge clears after opening
- test_opening_chat_loads_many_messages: verify all 50 messages load, not just last few

All 28 chat_list tests pass.

tests/helpers/fake_tdclient.rs

@@ -46,6 +46,7 @@ pub struct FakeTdClient {
     pub searched_queries: Arc<Mutex<Vec<SearchQuery>>>,
     pub viewed_messages: Arc<Mutex<Vec<(i64, Vec<i64>)>>>, // (chat_id, message_ids)
     pub chat_actions: Arc<Mutex<Vec<(i64, String)>>>, // (chat_id, action)
+    pub pending_view_messages: Arc<Mutex<Vec<(ChatId, Vec<MessageId>)>>>, // Очередь для отметки как прочитанные
     
     // Update channel для симуляции событий
     pub update_tx: Arc<Mutex<Option<mpsc::UnboundedSender<TdUpdate>>>>,
@@ -119,6 +120,7 @@ impl Clone for FakeTdClient {
             searched_queries: Arc::clone(&self.searched_queries),
             viewed_messages: Arc::clone(&self.viewed_messages),
             chat_actions: Arc::clone(&self.chat_actions),
+            pending_view_messages: Arc::clone(&self.pending_view_messages),
             update_tx: Arc::clone(&self.update_tx),
             simulate_delays: self.simulate_delays,
             fail_next_operation: Arc::clone(&self.fail_next_operation),
@@ -151,6 +153,7 @@ impl FakeTdClient {
             searched_queries: Arc::new(Mutex::new(vec![])),
             viewed_messages: Arc::new(Mutex::new(vec![])),
             chat_actions: Arc::new(Mutex::new(vec![])),
+            pending_view_messages: Arc::new(Mutex::new(vec![])),
             update_tx: Arc::new(Mutex::new(None)),
             simulate_delays: false,
             fail_next_operation: Arc::new(Mutex::new(false)),