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/port-map/EterLib/GrpImageTexture.cpp.json

@@ -28,20 +28,20 @@
     "CGraphicImageTexture::CreateDDSTexture": {
       "status": "ADAPTED",
       "impl": [
-        "extension/src/dxt.cpp:decode",
-        "native_render/main.cpp:get_gpu_texture",
-        "native_render/main.cpp:upload_texture"
+        "src/host/dxt.cpp:decode",
+        "src/host/main.cpp:get_gpu_texture",
+        "src/host/main.cpp:upload_texture"
       ],
-      "test": "extension/tests/dxt_decode_test.cpp",
+      "test": "tests/port/dxt_decode_test.cpp",
       "note": "The platform CreateDDSTexture member is a stub; its level logic lives in the texture decode/upload the renderer does. mipmapCount = max(1, min(dwMipMapCount, MAX_MIPLEVELS=12)), level i read at sum(dwLinearSize>>2k) with CDXTCImage::Copy's dwLinearSize>>2i bytes (the rest zero, uninitialised in 40250), decoded to RGBA8 (no GPU DXT) and uploaded as file levels, not regenerated. Divergence: without DDSD_MIPMAPCOUNT, or with DDSD_PITCH, 40250 creates the extra levels uninitialised; here that is one level. IsLowTextureMemory's uTexBias level skip is not applied (the port's ms_isLowTextureMemory is false). The far-terrain look NEEDS_LIVE."
     },
     "CGraphicImageTexture::CreateFromMemoryFile": {
       "status": "ADAPTED",
       "impl": [
-        "extension/src/platform/EterLib/GrpImageTexture.cpp:CGraphicImageTexture::CreateFromMemoryFile",
-        "native_render/main.cpp:get_gpu_texture"
+        "src/platform/EterLib/GrpImageTexture.cpp:CGraphicImageTexture::CreateFromMemoryFile",
+        "src/host/main.cpp:get_gpu_texture"
       ],
-      "test": "extension/tests/dxt_decode_test.cpp",
+      "test": "tests/port/dxt_decode_test.cpp",
       "note": "The platform body records only the size and file name; the renderer decodes the bytes. 40250 dispatch is kept: a DXT DDS takes the CreateDDSTexture levels, anything else takes D3DXCreateTextureFromFileInMemoryEx(MipLevels=D3DX_DEFAULT), i.e. a full generated chain (vkCmdBlitImage linear, instead of D3DX's box filter). The invented is_ui_tex rule (no mips for icon/, ui/, locale/ and textures <=128px) was removed. Memory textures (mem:, 40250 CreateTexture levels=1) get one level. GRAPHICS_CAPS_HALF_SIZE_IMAGE/low-memory A4R4G4B4 re-encode is not applied."
     },
     "CGraphicImageTexture::SetFileName": {