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.

tests/test_game_data.py

@@ -2,7 +2,6 @@ import datetime
 import json
 import pickle
 from pathlib import Path
-from typing import Any
 
 import pytest
 
@@ -18,7 +17,7 @@ from pqcli.game_data import (
 from pqcli.mechanic import Player, Stats, monster_task
 
 
-def write(directory: Path, name: str, value: Any) -> Path:
+def write(directory: Path, name: str, value: object) -> Path:
     path = directory / f"{name}.json"
     path.write_text(json.dumps(value), encoding="utf-8")
     return path
@@ -98,7 +97,7 @@ def test_unknown_file_warns(
     ],
 )
 def test_invalid_override_raises(
-    tmp_path: Path, name: str, value: Any, message: str
+    tmp_path: Path, name: str, value: object, message: str
 ) -> None:
     write(tmp_path, name, value)
     with pytest.raises(DataError) as excinfo: