feat: toggle hidden directories in cd-browser with . key

src/app/ui.py

@@ -145,7 +145,8 @@ class TerminalUI:
             stdscr.refresh()
             return
 
-        path_text = str(navigator.current_path)
+        hidden_status = "on" if navigator.show_hidden else "off"
+        path_text = f"{navigator.current_path} [hidden: {hidden_status}]"
         stdscr.addnstr(0, 0, path_text, width - 1)
 
         lines = build_render_lines(navigator)
@@ -282,6 +283,11 @@ class TerminalUI:
             self._tree_scroll_offset = 0
             return None
 
+        if key == ord("."):
+            navigator.toggle_hidden()
+            self._tree_scroll_offset = 0
+            return None
+
         if key in (curses.KEY_ENTER, 10, 13):
             return navigator.selected_entry.path