Add (very!) rough simulation of frozen combat.

There are some TODOs here but th behavior is flagged off by default. The
biggest TODO here is that the time spent frozen is not simulated, so
flights that are engaged by SAMs will unfreeze, move slightly, then re-
freeze.

https://github.com/dcs-liberation/dcs_liberation/issues/1680

game/sim/combat/joinablecombat.py

@@ -2,8 +2,10 @@ from __future__ import annotations
 
 from abc import ABC, abstractmethod
 from collections.abc import Iterator
+from datetime import timedelta
 from typing import TYPE_CHECKING
 
+from game.ato.flightstate import InCombat, InFlight
 from .frozencombat import FrozenCombat
 
 if TYPE_CHECKING:
@@ -11,8 +13,8 @@ if TYPE_CHECKING:
 
 
 class JoinableCombat(FrozenCombat, ABC):
-    def __init__(self, flights: list[Flight]) -> None:
-        super().__init__()
+    def __init__(self, freeze_duration: timedelta, flights: list[Flight]) -> None:
+        super().__init__(freeze_duration)
         self.flights = flights
 
     @abstractmethod
@@ -20,7 +22,10 @@ class JoinableCombat(FrozenCombat, ABC):
         ...
 
     def join(self, flight: Flight) -> None:
+        assert isinstance(flight.state, InFlight)
+        assert not isinstance(flight.state, InCombat)
         self.flights.append(flight)
+        flight.set_state(InCombat(flight.state, self))
 
     def iter_flights(self) -> Iterator[Flight]:
         yield from self.flights