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/Include/traceback.h

@@ -0,0 +1,31 @@
+
+#ifndef Py_TRACEBACK_H
+#define Py_TRACEBACK_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct _frame;
+
+/* Traceback interface */
+
+typedef struct _traceback {
+	PyObject_HEAD
+	struct _traceback *tb_next;
+	struct _frame *tb_frame;
+	int tb_lasti;
+	int tb_lineno;
+} PyTracebackObject;
+
+PyAPI_FUNC(int) PyTraceBack_Here(struct _frame *);
+PyAPI_FUNC(int) PyTraceBack_Print(PyObject *, PyObject *);
+PyAPI_FUNC(int) _Py_DisplaySourceLine(PyObject *, const char *, int, int);
+
+/* Reveal traceback type so we can typecheck traceback objects */
+PyAPI_DATA(PyTypeObject) PyTraceBack_Type;
+#define PyTraceBack_Check(v) (Py_TYPE(v) == &PyTraceBack_Type)
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_TRACEBACK_H */