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>

third_party/CMakeLists.txt

@@ -0,0 +1,43 @@
+# Vendored native dependencies for the 40250 port and SDL/Vulkan client.
+#
+# Everything is built from source as static libraries (the Android NDK and iOS
+# SDK sysroots have none of them):
+#
+#   cryptopp        <- Crypto++ (classic protocol cipher)
+#   freetype        <- FreeType 2.13.3 (platform font adapter)
+#   minilzo         <- vendored miniLZO source (LZO1X, ~4 files) — see NOTICE
+#
+# See docs/THIRD-PARTY.md for versions / licenses. liblzo2 (and thus miniLZO) is
+# GPL: fine for this internal, non-published project — same footing as
+# src/gr2/src/oodle1.c — but must be swapped or re-licensed before any release.
+
+# Android links these static libraries into libmain.so, so they must be PIC.
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+# --- Crypto++ (MT_PROTOCOL=classic cipher) ----------------------------------
+add_subdirectory(cryptopp EXCLUDE_FROM_ALL)
+
+# --- FreeType (platform font adapter: EterLib/GrpFontTexture) ----------------
+add_subdirectory(freetype-2.13.3 EXCLUDE_FROM_ALL)
+
+# --- miniLZO ------------------------------------------------------------------
+# One translation unit, an amalgamation generated from the LZO sources. Its
+# public API (<lzo/lzo1x.h> via the shim header) is a strict subset of full LZO.
+add_library(minilzo STATIC minilzo/minilzo.c)
+target_include_directories(minilzo PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}/minilzo")
+set_target_properties(minilzo PROPERTIES C_STANDARD 99)
+add_library(mt3p::minilzo ALIAS minilzo)
+
+# --- CPython 2.7.18 (embedded 40250 script layer, 批次 2P) ----------------------
+# On everywhere the interpreter has a pyconfig.h: since step 2 the ported ScriptLib is part of
+# port_logic. Windows has none yet (MinGW vs MSVC, see cpython-2.7.18/CMakeLists.txt), so the
+# script layer is left out of that build until 批次 2P step 4 decides.
+if(WIN32)
+    set(MT_EMBED_PYTHON_DEFAULT OFF)
+else()
+    set(MT_EMBED_PYTHON_DEFAULT ON)
+endif()
+option(MT_EMBED_PYTHON "Build the embedded CPython 2.7.18 static library" ${MT_EMBED_PYTHON_DEFAULT})
+if(MT_EMBED_PYTHON)
+    add_subdirectory(cpython-2.7.18)
+endif()