misc: fix all ty diagnostics

ty reported 20 diagnostics, and 0.0.89 adds a few more; this clears
them all without suppressions.

- The quest monster is held in a local before being stored on the
  quest book, so its name no longer reads from an Optional.
- PgUp/PgDn narrow the focused window with isinstance against a
  runtime-checkable PageScrollable protocol instead of hasattr.
- The ^t cheat used to monkeypatch SignalMixin.emit. SignalMixin now
  has a muted() context manager that emit() checks, and it restores
  emission even if a tick raises.
- GameView keeps its children as GameWindow, a protocol declaring
  stop() and sync(), so the cheat's resync type-checks.
- curses.ascii is imported explicitly where it is used.
- ProgressBarWindow is now Focusable itself, instead of calling
  Focusable.focus_standout() on a class that is not Focusable. Its
  four subclasses drop the duplicate Focusable base; the MRO and
  initialisation order are unchanged.
- MainMenu narrows the Optional pad before colouring the logo.
- The tests that record tasks assert player.task is set.
- Context managers are annotated as Generator rather than Iterator,
  which ty flags as deprecated for @contextmanager.
- The redundant cast() around getch() is gone.
- The frozen GameData test assigns through setattr(), since the
  direct assignment is an error by design.

Bug fixes:

- ListBox.select(None) crashed on `None < 0`; it now clears the
  selection, as DataTable.select(None) already does.
- ListBox.get() caught ValueError, which indexing never raises; it
  now catches IndexError, so an out-of-range index returns None as
  intended.

pqcli/ui/curses/views/roster_view.py

@@ -38,15 +38,17 @@ class MainMenu(Menu):
             scr_height=scr_height,
             scr_width=scr_width,
         )
+        pad = self._pad
+        assert pad is not None
         if has_colors():
             for y in range(len(self._header_lines)):
-                self._pad.chgat(y, 0, curses.color_pair(COLOR_LOGO))
-            self._pad.chgat(3, 29, 5, curses.color_pair(COLOR_LOGO_ALT))
-            self._pad.chgat(4, 29, 5, curses.color_pair(COLOR_LOGO_ALT))
-            self._pad.chgat(5, 32, 4, curses.color_pair(COLOR_LOGO_ALT))
-            self._pad.chgat(5, 27, 4, curses.color_pair(COLOR_LOGO_ALT))
-            self._pad.chgat(6, 34, 2, curses.color_pair(COLOR_LOGO_ALT))
-            self._pad.chgat(6, 27, 2, curses.color_pair(COLOR_LOGO_ALT))
+                pad.chgat(y, 0, curses.color_pair(COLOR_LOGO))
+            pad.chgat(3, 29, 5, curses.color_pair(COLOR_LOGO_ALT))
+            pad.chgat(4, 29, 5, curses.color_pair(COLOR_LOGO_ALT))
+            pad.chgat(5, 32, 4, curses.color_pair(COLOR_LOGO_ALT))
+            pad.chgat(5, 27, 4, curses.color_pair(COLOR_LOGO_ALT))
+            pad.chgat(6, 34, 2, curses.color_pair(COLOR_LOGO_ALT))
+            pad.chgat(6, 27, 2, curses.color_pair(COLOR_LOGO_ALT))
 
 
 class RosterView(BaseView):