port: complete python ledger mapping, audio commands bridge and platform stubs

- Added Client/root (74 modules, 3350 funcs) mapped to RUN_AS_IS
- Added UserInterface/PythonNetworkStreamModule.cpp.json mapped to PORTED
- Implemented AudioCommands queue bridging MilesLib SoundManager to Godot AudioDriver
- Implemented AudioDriver node for BGM crossfading, 2D UI SFX and 3D spatial sounds
- Implemented core platform stubs in PythonApplication, GrpScreen, and PythonGraphic
- Passed all 12 port tests (port_gate macos) and python_game_render_test

project/client_main.gd

@@ -45,6 +45,9 @@ func _start_port_route() -> void:
 	var world: Node3D = preload("res://python_3d_surface.gd").new()
 	world.name = "Python3DSurface"
 	add_child(world)
+	var audio: Node = preload("res://audio_driver.gd").new()
+	audio.name = "AudioDriver"
+	add_child(audio)
 	var err: String = surface.run_app()
 	if err != "":
 		printerr("port: " + err)