random: port Alea, one generator per character

pqcli used Python's global Mersenne Twister, seeded once from the clock.
Upstream uses Johannes Baagøe's Alea, with Random(n) = uint32() % n, and
keeps the generator state with each character. The port matches the JS
output bit for bit, including UTF-16 seeding of non-BMP characters.

Each Player now owns an Alea that is pickled with the save, and
Simulation.tick draws from it. Saves without one get a fresh generator.
As upstream does, a new character's game continues from the state the
kept stat roll was made from.

The parity traces are re-recorded, since every random number changes.

pqcli/ui/curses/views/create_character_view/choose_character_stats_view.py

@@ -55,7 +55,7 @@ class ChooseCharacterStatsView(BaseView):
             elif self._active_widget == 1:
                 self._stats = self._stats_builder.unroll()
             elif self._active_widget == 2:
-                self.on_confirm(self._stats)
+                self.on_confirm(self._stats, self._stats_builder.seed)
             elif self._active_widget == 3:
                 self.on_cancel()
             else:
@@ -68,7 +68,7 @@ class ChooseCharacterStatsView(BaseView):
             self._stats = self._stats_builder.unroll()
 
         elif key == curses.KEY_F10:
-            self.on_confirm(self._stats)
+            self.on_confirm(self._stats, self._stats_builder.seed)
 
         elif key in KEYS_CYCLE:
             self._active_widget = (self._active_widget + 1) % 4