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/cpython-2.7.18/Lib/sre.py

@@ -0,0 +1,13 @@
+"""This file is only retained for backwards compatibility.
+It will be removed in the future.  sre was moved to re in version 2.5.
+"""
+
+import warnings
+warnings.warn("The sre module is deprecated, please import re.",
+              DeprecationWarning, 2)
+
+from re import *
+from re import __all__
+
+# old pickles expect the _compile() reconstructor in this module
+from re import _compile