refactor: split main_input.rs into modular handlers (1199→164 lines)

Split monolithic input handler into 5 specialized modules:
- handlers/chat.rs (452 lines) - chat keyboard input
- handlers/modal.rs (316 lines) - modal dialogs
- handlers/chat_list.rs (142 lines) - chat list navigation
- handlers/search.rs (140 lines) - search functionality
- handlers/compose.rs (80 lines) - forward/reply/edit modes

Changes:
- main_input.rs: 1199→164 lines (removed 1035 lines, -86%)
- Preserved existing handlers: clipboard, global, profile
- Created clean router pattern in main_input.rs
- Fixed keybinding conflict: Ctrl+I→Ctrl+U for profile
- Fixed modifier handling in chat input (ignore Ctrl/Alt chars)
- Updated CONTEXT.md with refactoring metrics
- Updated ROADMAP.md: Phase 13 Etap 1 marked as DONE

Phase 13 Etap 1: COMPLETED (100%)

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

src/input/handlers/search.rs

@@ -0,0 +1,141 @@
+//! Search input handlers
+//!
+//! Handles keyboard input for search functionality, including:
+//! - Chat list search mode
+//! - Message search mode
+//! - Search query input
+
+use crate::app::App;
+use crate::tdlib::TdClientTrait;
+use crate::types::{ChatId, MessageId};
+use crate::utils::with_timeout;
+use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
+use std::time::Duration;
+
+// Import from chat_list module
+use super::chat_list::open_chat_and_load_data;
+
+/// Обработка режима поиска по чатам
+/// 
+/// Обрабатывает:
+/// - Редактирование поискового запроса (Backspace, Char)
+/// - Навигацию по отфильтрованному списку (Up/Down)
+/// - Открытие выбранного чата (Enter)
+/// - Отмену поиска (Esc)
+pub async fn handle_chat_search_mode<T: TdClientTrait>(app: &mut App<T>, key: KeyEvent, command: Option<crate::config::Command>) {
+    match command {
+        Some(crate::config::Command::Cancel) => {
+            app.cancel_search();
+        }
+        Some(crate::config::Command::SubmitMessage) => {
+            app.select_filtered_chat();
+            if let Some(chat_id) = app.get_selected_chat_id() {
+                open_chat_and_load_data(app, chat_id).await;
+            }
+        }
+        Some(crate::config::Command::MoveDown) => {
+            app.next_filtered_chat();
+        }
+        Some(crate::config::Command::MoveUp) => {
+            app.previous_filtered_chat();
+        }
+        _ => {
+            match key.code {
+                KeyCode::Backspace => {
+                    app.search_query.pop();
+                    app.chat_list_state.select(Some(0));
+                }
+                KeyCode::Char(c) => {
+                    app.search_query.push(c);
+                    app.chat_list_state.select(Some(0));
+                }
+                _ => {}
+            }
+        }
+    }
+}
+
+/// Обработка режима поиска по сообщениям в открытом чате
+/// 
+/// Обрабатывает:
+/// - Навигацию по результатам поиска (Up/Down/N/n)
+/// - Переход к выбранному сообщению (Enter)
+/// - Редактирование поискового запроса (Backspace, Char)
+/// - Выход из режима поиска (Esc)
+pub async fn handle_message_search_mode<T: TdClientTrait>(app: &mut App<T>, key: KeyEvent, command: Option<crate::config::Command>) {
+    match command {
+        Some(crate::config::Command::Cancel) => {
+            app.exit_message_search_mode();
+        }
+        Some(crate::config::Command::MoveUp) => {
+            app.select_previous_search_result();
+        }
+        Some(crate::config::Command::MoveDown) => {
+            app.select_next_search_result();
+        }
+        Some(crate::config::Command::SubmitMessage) => {
+            if let Some(msg_id) = app.get_selected_search_result_id() {
+                let msg_id = MessageId::new(msg_id);
+                let msg_index = app
+                    .td_client
+                    .current_chat_messages()
+                    .iter()
+                    .position(|m| m.id() == msg_id);
+
+                if let Some(idx) = msg_index {
+                    let total = app.td_client.current_chat_messages().len();
+                    app.message_scroll_offset = total.saturating_sub(idx + 5);
+                }
+                app.exit_message_search_mode();
+            }
+        }
+        _ => {
+            match key.code {
+                KeyCode::Char('N') => {
+                    app.select_previous_search_result();
+                }
+                KeyCode::Char('n') => {
+                    app.select_next_search_result();
+                }
+                KeyCode::Backspace => {
+                    let Some(mut query) = app.get_search_query().map(|s| s.to_string()) else {
+                        return;
+                    };
+                    query.pop();
+                    app.update_search_query(query.clone());
+                    perform_message_search(app, &query).await;
+                }
+                KeyCode::Char(c) => {
+                    let Some(mut query) = app.get_search_query().map(|s| s.to_string()) else {
+                        return;
+                    };
+                    query.push(c);
+                    app.update_search_query(query.clone());
+                    perform_message_search(app, &query).await;
+                }
+                _ => {}
+            }
+        }
+    }
+}
+
+/// Выполняет поиск по сообщениям с обновлением результатов
+pub async fn perform_message_search<T: TdClientTrait>(app: &mut App<T>, query: &str) {
+    let Some(chat_id) = app.get_selected_chat_id() else {
+        return;
+    };
+
+    if query.is_empty() {
+        app.set_search_results(Vec::new());
+        return;
+    }
+
+    if let Ok(results) = with_timeout(
+        Duration::from_secs(3),
+        app.td_client.search_messages(ChatId::new(chat_id), query),
+    )
+    .await
+    {
+        app.set_search_results(results);
+    }
+}