Speed up game tick by caching TGO threat regions.

Still more could be done here by caching the merged poly at the theater
level, but this goes a long way.

Aircraft commit regions are already cached (in the FlightState), so
those are already fairly fast. The combined A2A commit boundary could
also potentially be cached at the theater level.

game/sim/combat/samengagementzones.py

@@ -1,12 +1,12 @@
 from __future__ import annotations
 
 from collections.abc import Iterator
-from typing import Any, Optional, TYPE_CHECKING
+from typing import TYPE_CHECKING
 
 from dcs import Point
 from shapely.ops import unary_union
 
-from game.utils import dcs_to_shapely_point, meters
+from game.utils import dcs_to_shapely_point
 
 if TYPE_CHECKING:
     from game.theater import ConflictTheater, TheaterGroundObject
@@ -36,14 +36,7 @@ class SamEngagementZones:
         individual_zones = []
         for cp in theater.control_points_for(player):
             for tgo in cp.connected_objectives:
-                if (region := cls.threat_region(tgo)) is not None:
+                if (region := tgo.threat_poly()) is not None:
                     commit_regions.append(region)
                     individual_zones.append((tgo, region))
         return SamEngagementZones(unary_union(commit_regions), individual_zones)
-
-    @classmethod
-    def threat_region(cls, tgo: TheaterGroundObject) -> Optional[ThreatPoly]:
-        threat_range = tgo.max_threat_range()
-        if threat_range <= meters(0):
-            return None
-        return dcs_to_shapely_point(tgo.position).buffer(threat_range.meters)