misc: replace Any with precise types

Curses screens, windows and pads are typed as curses.window, and the
widgets that may get no parent window take curses.window | None.

- EventHandler is generic over a ParamSpec, so each handler declares
  the arguments it passes, and MenuView is generic over the item its
  on_confirm hands out. Choice callbacks take no arguments.
- Scrollable is generic over its items, which DataTable and ListBox
  fix to tuple[str, str] and str.
- random.choice() and choice_low() are generic over the sequence, so
  the casts at their call sites are gone. BasicUserInterface.menu()
  and util.first() are generic too.
- Signal callbacks and their payloads are Callable[..., object] and
  object, since emit() only forwards them.
- JSON values in game_data are object and narrowed by isinstance,
  and data files are Traversable.
- Signal handlers take an int and a FrameType | None, and
  list_players() takes a TextIO.
- The focus_standout() context managers return
  Generator[None, None, None].

Any remains in three places: Player.__setstate__, whose pickled
__dict__ holds values of every type; Focusable.__init__, a mixin that
passes *args and **kwargs through to the next class; and the values
load_game_data() collects, whose element type depends on the field
each one fills.

pqcli/ui/curses/widgets/menu.py

@@ -1,6 +1,5 @@
 import curses
 import curses.ascii
-from typing import Any
 
 from pqcli.ui.curses.util import KEYS_CYCLE, KEYS_DOWN, KEYS_UP, Choice
 from pqcli.ui.curses.widgets.focusable import focus_standout
@@ -29,7 +28,7 @@ class Menu(Widget):
         w = max(map(len, all_lines)) + 1
         h = len(all_lines) + 1
         pad = curses.newpad(h, w)
-        self._pad: Any | None = pad
+        self._pad: curses.window | None = pad
 
         for y, line in enumerate(self._header_lines):
             pad.move(y, 0)