chore: remove dead code and unnecessary allow(dead_code) attributes

Cleaned up warnings by removing unused code:
- Removed unused format_timestamp() function from utils.rs
- Removed unused len() method from LruCache
- Removed unused date field from ForwardInfo struct
- Removed unnecessary #[allow(dead_code)] attributes from:
  * AuthState enum (actually used)
  * ChatInfo struct (actually used)
  * TdClient impl block (actually used)

This reduces code noise and makes real warnings more visible.

Changes:
- 20 lines removed
- 1 line added
- 6 files changed

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

src/tdlib/auth.rs

@@ -6,7 +6,6 @@ use tdlib_rs::functions;
 /// Отслеживает текущий этап аутентификации пользователя,
 /// от инициализации TDLib до полной авторизации.
 #[derive(Debug, Clone, PartialEq)]
-#[allow(dead_code)]
 pub enum AuthState {
     /// Ожидание параметров TDLib (начальное состояние).
     WaitTdlibParameters,

src/tdlib/client.rs

@@ -59,7 +59,6 @@ pub struct TdClient {
     pub network_state: NetworkState,
 }
 
-#[allow(dead_code)]
 impl TdClient {
     /// Creates a new TDLib client instance.
     ///
@@ -1102,7 +1101,7 @@ impl TdClient {
     fn extract_forward_info(&self, message: &TdMessage) -> Option<ForwardInfo> {
         message.forward_info.as_ref().map(|info| {
             let sender_name = self.get_origin_sender_name(&info.origin);
-            ForwardInfo { sender_name, date: info.date }
+            ForwardInfo { sender_name }
         })
     }
 

src/tdlib/messages.rs

@@ -720,7 +720,6 @@ impl MessageManager {
             if let tdlib_rs::enums::MessageOrigin::User(origin_user) = &fi.origin {
                 Some(ForwardInfo {
                     sender_name: format!("User {}", origin_user.sender_user_id),
-                    date: fi.date,
                 })
             } else {
                 None

src/tdlib/types.rs

@@ -3,7 +3,6 @@ use tdlib_rs::types::TextEntity;
 use crate::types::{ChatId, MessageId};
 
 #[derive(Debug, Clone)]
-#[allow(dead_code)]
 pub struct ChatInfo {
     pub id: ChatId,
     pub title: String,
@@ -41,9 +40,6 @@ pub struct ReplyInfo {
 pub struct ForwardInfo {
     /// Имя оригинального отправителя
     pub sender_name: String,
-    /// Дата оригинального сообщения (для будущего использования)
-    #[allow(dead_code)]
-    pub date: i32,
 }
 
 /// Информация о реакции на сообщение

src/tdlib/users.rs

@@ -89,12 +89,6 @@ where
     pub fn contains_key(&self, key: &K) -> bool {
         self.map.contains_key(key)
     }
-
-    /// Количество элементов
-    #[allow(dead_code)]
-    pub fn len(&self) -> usize {
-        self.map.len()
-    }
 }
 
 /// Кэш информации о пользователях Telegram.