Add CUDA NGX Ray Reconstruction support

Run the signed CUDA-capable denoiser through feature 13 with independent D/E presets, pre-Init discovery, per-frame guide and camera snapshots, normalized integer guide staging, paired alpha output, and recorded-resource retirement.

Add the required ZLUDA/LLVM patch, behavioral configuration tests, GPU harness coverage, optional denoiser installation and packaging, and tested support limitations. Preserve upstream attribution and distinguish LLVM licensing from the ZLUDA portions of the patch.

tests/test_ray_reconstruction.py

@@ -0,0 +1,67 @@
+"""Preset isolation, invalid-setting rejection, and environment precedence."""
+import os
+from pathlib import Path
+import subprocess
+import tempfile
+import unittest
+
+ROOT = Path(__file__).resolve().parents[1]
+CONFIG = ROOT / "scripts" / "d4r_config.py"
+RR_VARIABLES = ("D4R_RR_ENABLE", "D4R_RR_PRESET")
+
+
+def run_config(text, **overrides):
+    """Runs d4r_config.py over `text`; returns (exit code, exports of interest).
+
+    d4r_config.py also emits its own defaults for unrelated variables, so the result is
+    filtered to the Ray Reconstruction and Super Sampling preset variables - the ones whose
+    independence from each other is under test here.
+    """
+    with tempfile.TemporaryDirectory() as directory:
+        ini = Path(directory) / "d4r.ini"
+        ini.write_text(text)
+        env = dict(os.environ)
+        for name in RR_VARIABLES + ("D4R_DLSS_PRESET",):
+            env.pop(name, None)
+        env.update(overrides)
+        result = subprocess.run(["python3", str(CONFIG), "--config", str(ini)], env=env,
+                                capture_output=True, text=True)
+    interesting = set(RR_VARIABLES) | {"D4R_DLSS_PRESET"}
+    decided = {}
+    for line in result.stdout.splitlines():
+        if line.startswith("export "):
+            key, _, value = line[len("export "):].partition("=")
+            if key in interesting:
+                decided[key] = value
+    return result.returncode, decided
+
+
+class RayReconstructionConfigTests(unittest.TestCase):
+    def test_rr_and_super_sampling_presets_do_not_collide(self):
+        code, decided = run_config("[RayReconstruction]\nEnable = true\nModel = E\n[DLSS]\nModel = K\n")
+        self.assertEqual(code, 0)
+        self.assertEqual(decided["D4R_RR_ENABLE"], "1")
+        self.assertEqual(decided["D4R_RR_PRESET"], "5")     # Ray Reconstruction preset E
+        self.assertEqual(decided["D4R_DLSS_PRESET"], "11")  # Super Sampling preset K
+
+    def test_invalid_rr_settings_are_rejected_rather_than_guessed(self):
+        for text in ("[RayReconstruction]\nModel = F\n",
+                     "[RayReconstruction]\nModel = K\n",
+                     "[RayReconstruction]\nEnable = maybe\n"):
+            with self.subTest(ini=text):
+                code, decided = run_config(text)
+                self.assertNotEqual(code, 0, f"accepted {text!r} as {decided}")
+                for name in RR_VARIABLES:
+                    self.assertNotIn(name, decided)
+
+    def test_environment_wins_over_the_ini(self):
+        # An explicitly exported variable is the user's decision and must survive.
+        code, decided = run_config("[RayReconstruction]\nEnable = true\nModel = E\n",
+                                   D4R_RR_ENABLE="0", D4R_RR_PRESET="4")
+        self.assertEqual(code, 0)
+        self.assertNotIn("D4R_RR_ENABLE", decided)
+        self.assertNotIn("D4R_RR_PRESET", decided)
+
+
+if __name__ == "__main__":
+    unittest.main()