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>

audit/contracts/lifecycle.platform-release.md

@@ -29,7 +29,7 @@
 - `project/asset_root.gd` / `asset_pack.gd` / `build-macos-client.sh` / `build-android.sh` / `project/export_presets.cfg`
   - macOS 脚本将 assets/bgm 复制到 app Resources，Android 使用 `assets.zip`/`asset_index.txt`，AssetRoot 支持环境变量、散文件、包内资源和可执行文件旁资源。
   - 当前没有 Windows 导出预设或 Windows GDExtension 构建脚本；资源链也不是 EterPack 的原生 eix/epk/CRC/更新流程，移动端还依赖外部 zip。
-- `oracle/*`
+- `tools/granny-oracle/*`
   - 有 Windows/Wine Granny 对拍工具和文档，但它是测试 oracle，不是客户端发布/崩溃/版本链。
 
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