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/cryptopp/hashfwd.h

@@ -0,0 +1,38 @@
+// hashfwd.h - written and placed in the public domain by Jeffrey Walton
+
+/// \file hashfwd.h
+/// \brief Forward declarations for hash functions used in signature encoding methods
+
+#ifndef CRYPTOPP_HASHFWD_H
+#define CRYPTOPP_HASHFWD_H
+
+#include "config.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+class SHA1;
+class SHA224;
+class SHA256;
+class SHA384;
+class SHA512;
+
+class SHA3_256;
+class SHA3_384;
+class SHA3_512;
+
+class SHAKE128;
+class SHAKE256;
+
+class Tiger;
+class RIPEMD128;
+class RIPEMD160;
+class Whirlpool;
+
+namespace Weak1 {
+  class MD2;
+  class MD5;
+}
+
+NAMESPACE_END
+
+#endif  // CRYPTOPP_HASHFWD_H