Add websocket event stream for sim updates.

As a proof of concept this only covers the flight positions.

game/server/eventstream/models.py

@@ -0,0 +1,25 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+from uuid import UUID
+
+from pydantic import BaseModel
+
+from game.server.leaflet import LeafletLatLon
+
+if TYPE_CHECKING:
+    from game import Game
+    from game.sim.gameupdateevents import GameUpdateEvents
+
+
+class GameUpdateEventsJs(BaseModel):
+    updated_flights: dict[UUID, LeafletLatLon]
+
+    @classmethod
+    def from_events(cls, events: GameUpdateEvents, game: Game) -> GameUpdateEventsJs:
+        return GameUpdateEventsJs(
+            updated_flights={
+                f[0].id: game.theater.point_to_ll(f[1]).as_list()
+                for f in events.updated_flights
+            }
+        )