ui/curses: wait for keys instead of polling

The main loop slept 100 ms whenever no key was pending, so keys took
up to a tick to register and every screen woke ten times a second.
Each view now declares how often it needs idle(): the game view keeps
its 100 ms tick, while menus wait for a key. getch() blocks for that
long, so keys register at once, and over 15 s in the roster menu the
process goes from about 300 wake-ups to 6.

pqcli/ui/curses/views/game_view/__init__.py

@@ -42,6 +42,8 @@ class PageScrollable(Protocol):
 
 
 class GameView(BaseView):
+    idle_interval = 100
+
     def __init__(
         self,
         screen: curses.window,