v1.8.23: fix Ctrl+V/C/X/A/Z for non-Latin keyboard layouts, add Entry undo/redo

- Global keycode-based handler for Ctrl shortcuts (works with Russian, Chinese, any layout)
- Tkinter maps <<Paste>> to <Control-v> by keysym which fails on non-Latin layouts
- New handler intercepts <Control-Key> at 'all' level, checks keycodes and generates correct virtual events
- Added Undo/Redo support for Entry widgets (tk.Entry has no built-in undo)
- Tab switch focus management: terminal releases focus when switching away

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gui/tabs/terminal_tab.py

@@ -123,7 +123,9 @@ class TerminalTab(ctk.CTkFrame):
                     self._terminal.set_status(
                         t("term_connected").format(alias=alias), "#44cc44"
                     )
-                    self._terminal.focus_terminal()
+                    # Only grab focus if terminal tab is currently visible
+                    if self._terminal.winfo_ismapped():
+                        self._terminal.focus_terminal()
                 self.after(0, _set_session)
             except Exception as e:
                 self.after(0, lambda: self._terminal.set_status(