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>

tests/gr2/animation.cpp

@@ -0,0 +1,56 @@
+#include <gr2/types.h>
+
+#include <cmath>
+#include <cstdio>
+#include <vector>
+
+int main() {
+	// ScaleShearCurve uses 9 values per control point. A quadratic span reads
+	// three control points, so this is the regression case for the former 3*4
+	// stack buffer in Curve::eval().
+	gr2::Curve curve;
+	curve.degree = 2;
+	curve.dim = 9;
+	curve.knots = {0.0f, 1.0f, 2.0f};
+	curve.controls.resize(27);
+	for (size_t i = 0; i < curve.controls.size(); ++i) {
+		curve.controls[i] = 1.0f + static_cast<float>(i) * 0.01f;
+	}
+
+	float out[9] = {};
+	curve.eval(0.5f, out);
+	for (float value : out) {
+		if (!std::isfinite(value)) {
+			std::fprintf(stderr, "non-finite 9D curve output\n");
+			return 1;
+		}
+	}
+
+	// BoneTrack::sample fills SRT components and flags; sample_local = compose(sample).
+	gr2::BoneTrack track;
+	track.position.degree = 1;
+	track.position.dim = 3;
+	track.position.knots = {0.0f, 1.0f};
+	track.position.controls = {0.0f, 0.0f, 0.0f, 2.0f, 4.0f, 6.0f};
+	track.orientation.degree = 0;
+	track.orientation.dim = 4;
+	track.orientation.knots = {0.0f};
+	track.orientation.controls = {0.0f, 0.0f, 0.70710678f, 0.70710678f}; // 90 deg about Z
+	gr2::Transform x;
+	track.sample(0.5f, x);
+	if (x.flags != 3 || std::fabs(x.position[0] - 1.0f) > 1e-5f || std::fabs(x.position[2] - 3.0f) > 1e-5f) {
+		std::fprintf(stderr, "BoneTrack::sample flags=%u pos=%f,%f,%f\n", x.flags, x.position[0], x.position[1], x.position[2]);
+		return 1;
+	}
+	gr2::Animation anim;
+	anim.tracks.push_back(track);
+	std::vector<gr2::Mat4> local;
+	anim.sample_local(0.5f, local);
+	const gr2::Mat4 m = gr2::compose(x);
+	// Row-major composite: row 0 is the rotated X axis (0,1,0); translation in 12..14.
+	if (local.size() != 1 || local[0] != m || std::fabs(m[1] - 1.0f) > 1e-5f || std::fabs(m[12] - 1.0f) > 1e-5f) {
+		std::fprintf(stderr, "compose mismatch m[1]=%f m[12]=%f\n", m[1], m[12]);
+		return 1;
+	}
+	return 0;
+}