refactor: cleanup unused code and warnings

Comprehensive cleanup of unused methods, dead code, and compiler warnings:

## Removed Methods (15):
- Duplicate delegation methods: is_authenticated, get_typing_text, get_user_name from TdClient
- Obsolete methods: TdClient::init() (duplicated in main.rs)
- Unused getters: UserCache::{get_username, get_name, get_user_id_by_chat}
- Unused builder methods: MessageBuilder::{edited, add_reaction}
- Unused utility: ChatState::is_normal()
- Dead code: HotkeysConfig::{matches, key_matches} (kept for tests)
- Unused method: UserCache::register_private_chat()
- Getter replaced with direct field access: MessageInfo::edit_date()

## Removed Module:
- error.rs - Unused error handling module (TeletuiError, ErrorVariant, IntoTeletuiError)

## Removed Constants (8):
- EMOJI_PICKER_COLUMNS, EMOJI_PICKER_ROWS, MAX_INPUT_HEIGHT
- MIN_TERMINAL_WIDTH, MIN_TERMINAL_HEIGHT
- TDLIB_CHAT_LIMIT, MAX_USERNAME_DISPLAY_LENGTH, MESSAGE_TEXT_INDENT

## Fixed Warnings:
- Removed unused imports (8 instances)
- Fixed unreachable patterns (10 instances)
- Fixed irrefutable if let patterns (2 instances)
- Fixed unused variables (1 instance)
- Removed dead_code annotations where appropriate

## Improvements:
- Integrated Config::load_credentials() into TdClient::new() for better credential management
- Replaced edit_date() getter with direct field access (message.metadata.edit_date)
- Updated tests to use direct field access instead of removed getters

## Test Results:
All tests passing: 499 passed, 0 failed

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

src/tdlib/client.rs

@@ -62,18 +62,28 @@ pub struct TdClient {
 impl TdClient {
     /// Creates a new TDLib client instance.
     ///
-    /// Reads API credentials from environment variables `API_ID` and `API_HASH`.
+    /// Reads API credentials from:
+    /// 1. ~/.config/tele-tui/credentials file
+    /// 2. Environment variables `API_ID` and `API_HASH` (fallback)
+    ///
     /// Initializes all managers and sets initial network state to Connecting.
     ///
     /// # Returns
     ///
     /// A new `TdClient` instance ready for authentication.
     pub fn new() -> Self {
-        let api_id = env::var("API_ID")
-            .unwrap_or_else(|_| "0".to_string())
-            .parse()
-            .unwrap_or(0);
-        let api_hash = env::var("API_HASH").unwrap_or_default();
+        // Пробуем загрузить credentials из Config (файл или env)
+        let (api_id, api_hash) = crate::config::Config::load_credentials()
+            .unwrap_or_else(|_| {
+                // Fallback на прямое чтение из env (старое поведение)
+                let api_id = env::var("API_ID")
+                    .unwrap_or_else(|_| "0".to_string())
+                    .parse()
+                    .unwrap_or(0);
+                let api_hash = env::var("API_HASH").unwrap_or_default();
+                (api_id, api_hash)
+            });
+
         let client_id = tdlib_rs::create_client();
 
         Self {
@@ -91,15 +101,6 @@ impl TdClient {
 
     // Делегирование к auth
 
-    /// Checks if the user is authenticated.
-    ///
-    /// # Returns
-    ///
-    /// `true` if authentication is complete, `false` otherwise.
-    pub fn is_authenticated(&self) -> bool {
-        self.auth.is_authenticated()
-    }
-
     /// Sends phone number for authentication.
     ///
     /// This is the first step of the authentication flow.
@@ -213,10 +214,6 @@ impl TdClient {
         self.chat_manager.send_chat_action(chat_id, action).await
     }
 
-    pub fn get_typing_text(&self) -> Option<String> {
-        self.chat_manager.get_typing_text()
-    }
-
     pub fn clear_stale_typing_status(&mut self) -> bool {
         self.chat_manager.clear_stale_typing_status()
     }
@@ -318,10 +315,6 @@ impl TdClient {
     }
 
     // Делегирование к user_cache
-    pub async fn get_user_name(&self, user_id: UserId) -> String {
-        self.user_cache.get_user_name(user_id).await
-    }
-
     pub fn get_user_status_by_chat_id(&self, chat_id: ChatId) -> Option<&UserOnlineStatus> {
         self.user_cache.get_status_by_chat_id(chat_id)
     }
@@ -360,7 +353,6 @@ impl TdClient {
     pub async fn get_me(&self) -> Result<i64, String> {
         match functions::get_me(self.client_id).await {
             Ok(tdlib_rs::enums::User::User(user)) => Ok(user.id),
-            Ok(_) => Err("Неожиданный тип пользователя".to_string()),
             Err(e) => Err(format!("Ошибка получения текущего пользователя: {:?}", e)),
         }
     }
@@ -451,33 +443,6 @@ impl TdClient {
         &mut self.user_cache
     }
 
-    /// Инициализация TDLib
-    pub async fn init(&mut self) -> Result<(), String> {
-        let result = functions::set_tdlib_parameters(
-            false,                                 // use_test_dc
-            "tdlib_data".to_string(),              // database_directory
-            "".to_string(),                        // files_directory
-            "".to_string(),                        // database_encryption_key
-            true,                                  // use_file_database
-            true,                                  // use_chat_info_database
-            true,                                  // use_message_database
-            false,                                 // use_secret_chats
-            self.api_id,                           // api_id
-            self.api_hash.clone(),                 // api_hash
-            "en".to_string(),                      // system_language_code
-            "Desktop".to_string(),                 // device_model
-            "".to_string(),                        // system_version
-            env!("CARGO_PKG_VERSION").to_string(), // application_version
-            self.client_id,
-        )
-        .await;
-
-        match result {
-            Ok(_) => Ok(()),
-            Err(e) => Err(format!("Failed to set TDLib parameters: {:?}", e)),
-        }
-    }
-
     /// Обрабатываем одно обновление от TDLib
     pub fn handle_update(&mut self, update: Update) {
         match update {
@@ -845,10 +810,7 @@ impl TdClient {
 
     fn add_or_update_chat(&mut self, td_chat_enum: &TdChat) {
         // Pattern match to get inner Chat struct
-        let td_chat = match td_chat_enum {
-            TdChat::Chat(chat) => chat,
-            _ => return,
-        };
+        let TdChat::Chat(td_chat) = td_chat_enum;
 
         // Пропускаем удалённые аккаунты
         if td_chat.title == "Deleted Account" || td_chat.title.is_empty() {