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/focusable.py

@@ -8,7 +8,9 @@ from pqcli.ui.curses.event_handler import EventHandler
 
 
 @contextlib.contextmanager
-def focus_standout(focused: bool, win: Any) -> Generator:
+def focus_standout(
+    focused: bool, win: curses.window
+) -> Generator[None, None, None]:
     if focused:
         if has_colors():
             win.attron(curses.color_pair(COLOR_FOCUSED))
@@ -25,7 +27,7 @@ def focus_standout(focused: bool, win: Any) -> Generator:
 class Focusable:
     def __init__(self, *args: Any, **kwargs: Any) -> None:
         self._focused = False
-        self._on_focus_change = EventHandler()
+        self._on_focus_change = EventHandler[[]]()
         super().__init__(*args, **kwargs)
 
     @property
@@ -38,6 +40,8 @@ class Focusable:
         self._on_focus_change()
 
     @contextlib.contextmanager
-    def focus_standout(self, win: Any) -> Generator:
+    def focus_standout(
+        self, win: curses.window
+    ) -> Generator[None, None, None]:
         with focus_standout(self._focused, win):
             yield