port: FlyingData/Instance/ObjectManager/FlyTrace + effect/fly modules (batch 2 P1)

Verbatim copies of the 40250 flying-object units and the effect/fly
Python modules replace the pending CFlyingManager stand-in and the two
module stubs; initeffect/initfly run after initnet as in 40250 and the
flying manager gets the background as its map manager.
CMapManager::GetTerrainHeight is added over the native height tiles.
login_flow checks playersettingmodule registered the indexed fly data.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

audit/port-map/GameLib/MapManager.cpp.json

@@ -104,7 +104,12 @@
       "test": "project/python_game_render_test.gd"
     },
     "CMapManager::GetTerrainHeight": {
-      "status": "TODO"
+      "status": "ADAPTED",
+      "impl": [
+        "extension/src/platform/pending/GameLib/MapManager.cpp:CMapManager::GetTerrainHeight"
+      ],
+      "note": "CMapOutdoor::GetTerrainHeight: 40250 terrain triangle interpolation on packed height.raw. GetHeight forwards here until map objects are registered (CMapOutdoor::GetHeight's object half).",
+      "test": "extension/tests/port_login_flow_test.cpp"
     },
     "CMapManager::GetWaterHeight": {
       "status": "TODO"