移动端界面大小设置：默认 600 逻辑高，系统选项可选 600/700/800

Android 上 40250 界面原先固定按 800 逻辑像素高排版，弹窗文字在手机上只有约 1 mm 高。
- UIScaleMode.h + host ui_scale.cpp：逻辑高度来自保存的设置（默认 600），ui_height.cfg 保存，下次启动生效；
  桌面可用 MT_UI_HEIGHT 测试
- app.GetUIHeight/GetAppliedUIHeight/SetUIHeight
- mt_uiscale PORT 模块：系统选项对话框加高一行，"界面大小 大/中/小"，修改后聊天提示重启生效

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

src/port/UserInterface/PythonApplicationModule.cpp

@@ -4,6 +4,7 @@
 #include "PythonApplication.h"
 #include "../EterLib/Camera.h"
 #include "../../platform/EterBase/FrameRateMode.h" // PORT: frame-rate setting
+#include "../../platform/EterBase/UIScaleMode.h" // PORT: UI size setting
 
 extern bool PERF_CHECKER_RENDER_GAME;
 extern D3DXCOLOR g_fSpecularColor;
@@ -1207,6 +1208,27 @@ PyObject* appSetFrameRateMode(PyObject* poSelf, PyObject* poArgs)
 	return Py_BuildNone();
 }
 
+// PORT: the UI size setting of the system option dialog (platform/EterBase/UIScaleMode.h). GetUIHeight is
+// the player's choice (0 = unavailable), GetAppliedUIHeight the height this run lays out at.
+PyObject* appGetUIHeight(PyObject* poSelf, PyObject* poArgs)
+{
+	return Py_BuildValue("i", MtUIScale::Chosen().load());
+}
+
+PyObject* appGetAppliedUIHeight(PyObject* poSelf, PyObject* poArgs)
+{
+	return Py_BuildValue("i", MtUIScale::Applied().load());
+}
+
+PyObject* appSetUIHeight(PyObject* poSelf, PyObject* poArgs)
+{
+	int iHeight;
+	if (!PyTuple_GetInteger(poArgs, 0, &iHeight))
+		return Py_BuildException();
+	MtUIScale::Set(iHeight);
+	return Py_BuildNone();
+}
+
 void initapp()
 {
 	static PyMethodDef s_methods[] =
@@ -1275,6 +1297,9 @@ void initapp()
 		{ "GetRandom",					appGetRandom,					METH_VARARGS },
 		{ "GetFrameRateMode",			appGetFrameRateMode,			METH_VARARGS }, // PORT
 		{ "SetFrameRateMode",			appSetFrameRateMode,			METH_VARARGS }, // PORT
+		{ "GetUIHeight",				appGetUIHeight,					METH_VARARGS }, // PORT
+		{ "GetAppliedUIHeight",			appGetAppliedUIHeight,			METH_VARARGS }, // PORT
+		{ "SetUIHeight",				appSetUIHeight,					METH_VARARGS }, // PORT
 		{ "RunPythonFile",				appRunPythonFile,				METH_VARARGS },
 		{ "IsWebPageMode",				appIsWebPageMode,				METH_VARARGS },		
 		{ "ShowWebPage",				appShowWebPage,					METH_VARARGS },