layout: restructure into src/ tests/ android/ scripts/ tools/

- extension/src/{port,platform,codepage} -> src/; native_render -> src/host
  (+ dxt, shaders/); libgr2 -> src/gr2; extension/third_party -> third_party
- extension/tests -> tests/port, libgr2/tests -> tests/gr2
- android-native -> android (build.sh, push-client.sh moved in)
- script -> scripts; tools/40250 -> tools/server; oracle -> tools/granny-oracle;
  perf tools -> tools/perf
- all build trees under build/ (native, release, android, port-gate)
- xrender:: CMake aliases -> mt::; port-map ledger impl paths rewritten

No code changes. ctest 15/15, port_gate macos+android PASS, port_map check 0 errors.

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

docs/PYTHON-EMBED-EVAL.md

@@ -63,12 +63,12 @@
 ## 采用方案 A 后的结构
 
 ```
-extension/src/port/ScriptLib/PythonLauncher.cpp        # CPythonLauncher，几乎原样
-extension/src/port/EterPythonLib/PythonWindow*.cpp     # 窗口树、焦点、命中、事件：逻辑照搬
-extension/src/port/UserInterface/*Module.cpp           # net/player/chr/... 模块，调用已移植的 CPython* 单例
-extension/src/platform/ui/                             # 适配层：CGraphicImageInstance/CGraphicTextInstance
+src/port/ScriptLib/PythonLauncher.cpp        # CPythonLauncher，几乎原样
+src/port/EterPythonLib/PythonWindow*.cpp     # 窗口树、焦点、命中、事件：逻辑照搬
+src/port/UserInterface/*Module.cpp           # net/player/chr/... 模块，调用已移植的 CPython* 单例
+src/platform/ui/                             # 适配层：CGraphicImageInstance/CGraphicTextInstance
                                                        # 的绘制 -> Godot RenderingServer/CanvasItem
-extension/third_party/cpython-2.7.18/                  # 静态库
+third_party/cpython-2.7.18/                  # 静态库
 ```
 
 Godot 这边只剩一个宿主 Control：把输入转发给 `CPythonWindowManager`，每帧调用它的 Update/Render。
@@ -96,7 +96,7 @@ Godot 这边只剩一个宿主 Control：把输入转发给 `CPythonWindowManage
 
 ## 下一步
 
-1. ~~把 CPython 2.7.18 放进 `extension/third_party/`，共用源码/静态模块清单，但为各平台分别生成或维护
+1. ~~把 CPython 2.7.18 放进 `third_party/`，共用源码/静态模块清单，但为各平台分别生成或维护
    `pyconfig.h`~~，静态链接进 `libmtgodot`；
    源码和三平台配置已完成（2026-09-23，批次 2P step 1）：`mtpython` 静态库（`-DMTGODOT_EMBED_PYTHON=ON`）、
    `tools/py_embed/gen_pyconfig.sh`、ctest `python.embed`；macOS/Android/iOS 编译通过。