refactor: prepare handlers structure for future input refactoring

Preparation for splitting large input file (#2):
- Created src/input/handlers/ structure (7 modules)
  - clipboard.rs (~100 lines) - clipboard operations extracted
  - global.rs (~90 lines) - global commands (Ctrl+R/S/P/F) extracted
  - Stubs: profile.rs, search.rs, modal.rs, messages.rs, chat_list.rs
- main_input.rs remains monolithic (1139 lines)
  - Attempted full migration broke navigation - rolled back
  - Handlers remain as preparation for gradual migration

Updated documentation:
- REFACTORING_OPPORTUNITIES.md: #2.1 status updated
- CONTEXT.md: Added lesson about careful refactoring

Lesson learned: Critical input logic requires careful step-by-step
refactoring with functionality verification after each step.

Tests: 563 passed, 0 failed

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

src/input/handlers/global.rs

@@ -0,0 +1,85 @@
+//! Global commands that work from any screen
+//!
+//! Handles Ctrl+ combinations:
+//! - Ctrl+R: Refresh chats
+//! - Ctrl+S: Start search
+//! - Ctrl+P: View pinned messages
+//! - Ctrl+F: Search messages in chat
+
+use crate::app::App;
+use crate::types::ChatId;
+use crate::utils::{with_timeout, with_timeout_msg};
+use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
+use std::time::Duration;
+
+/// Обрабатывает глобальные команды (Ctrl+ combinations).
+///
+/// # Returns
+///
+/// `true` если команда была обработана, `false` если нет
+pub async fn handle_global_commands(app: &mut App, key: KeyEvent) -> bool {
+    let has_ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
+
+    match key.code {
+        KeyCode::Char('r') if has_ctrl => {
+            // Ctrl+R - обновить список чатов
+            app.status_message = Some("Обновление чатов...".to_string());
+            let _ = with_timeout(Duration::from_secs(5), app.td_client.load_chats(50)).await;
+            app.status_message = None;
+            true
+        }
+        KeyCode::Char('s') if has_ctrl => {
+            // Ctrl+S - начать поиск (только если чат не открыт)
+            if app.selected_chat_id.is_none() {
+                app.start_search();
+            }
+            true
+        }
+        KeyCode::Char('p') if has_ctrl => {
+            // Ctrl+P - режим просмотра закреплённых сообщений
+            handle_pinned_messages(app).await;
+            true
+        }
+        KeyCode::Char('f') if has_ctrl => {
+            // Ctrl+F - поиск по сообщениям в открытом чате
+            if app.selected_chat_id.is_some()
+                && !app.is_pinned_mode()
+                && !app.is_message_search_mode()
+            {
+                app.enter_message_search_mode();
+            }
+            true
+        }
+        _ => false,
+    }
+}
+
+/// Обрабатывает загрузку и отображение закреплённых сообщений
+async fn handle_pinned_messages(app: &mut App) {
+    if app.selected_chat_id.is_some() && !app.is_pinned_mode() {
+        if let Some(chat_id) = app.get_selected_chat_id() {
+            app.status_message = Some("Загрузка закреплённых...".to_string());
+            match with_timeout_msg(
+                Duration::from_secs(5),
+                app.td_client.get_pinned_messages(ChatId::new(chat_id)),
+                "Таймаут загрузки",
+            )
+            .await
+            {
+                Ok(messages) => {
+                    let messages: Vec<crate::tdlib::MessageInfo> = messages;
+                    if messages.is_empty() {
+                        app.status_message = Some("Нет закреплённых сообщений".to_string());
+                    } else {
+                        app.enter_pinned_mode(messages);
+                        app.status_message = None;
+                    }
+                }
+                Err(e) => {
+                    app.error_message = Some(e);
+                    app.status_message = None;
+                }
+            }
+        }
+    }
+}