feat: add d4r inference engines and Windows parity tooling

Add native K/M/RR inference engines, HIP kernels, replay and validation
harnesses, and Windows DLSS setup and runtime support. Include GPU
profiling tools, build and packaging scripts, platform integration
patches, and implementation documentation.

engine/gen_activation_m.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+"""Generate activation_m.glsl's ACT table: binary16 sigmoid, tanh and gate of every E4M3 code.
+
+usage: gen_activation_m.py            print the ACT declaration
+       gen_activation_m.py --check    exit 1 unless engine/activation_m.glsl holds exactly this table
+
+Row c is uvec2(tanh << 16 | sigmoid, gate) for the E4M3 value of code c:
+  sigmoid  1 / (1 + exp2(-1.442695 * x)) in f32, rounded to binary16
+  tanh     correctly rounded binary16 tanh(x)
+  gate     .5 * tanh(.5 * x) + .5 with each operation rounded to binary16
+The NaN codes (127, 255) give quiet NaN; the sigmoid keeps the input's sign, as f32 arithmetic propagates it.
+"""
+import math
+from pathlib import Path
+import re
+import sys
+
+import numpy as np
+
+GLSL = Path(__file__).resolve().parent / 'activation_m.glsl'
+NAN_ROWS = {127: (0x7e007e00, 0x7e00), 255: (0x7e00fe00, 0x7e00)}
+
+
+def e4m3(code):
+    sign = -1.0 if code & 128 else 1.0
+    exponent, mantissa = (code >> 3) & 15, code & 7
+    if exponent == 0:
+        return sign * mantissa / 8 * 2.0 ** -6
+    return sign * (1 + mantissa / 8) * 2.0 ** (exponent - 7)
+
+
+def bits(value):
+    return int(np.array(value, dtype=np.float16).view(np.uint16))
+
+
+def row(code):
+    if code in NAN_ROWS:
+        return NAN_ROWS[code]
+    x = e4m3(code)
+    with np.errstate(over='ignore'):
+        sigmoid = np.float32(1) / (np.float32(1) + np.exp2(np.float32(-1.442695) * np.float32(x), dtype=np.float32))
+    # float64 tanh rounded once to binary16 is correctly rounded for every E4M3 input (no value lies near a tie).
+    tanh = np.float16(math.tanh(x))
+    half = np.float16(0.5)
+    gate = np.float16(np.float16(half * np.float16(math.tanh(float(half * np.float16(x))))) + half)
+    return bits(tanh) << 16 | bits(sigmoid), bits(gate)
+
+
+def declaration():
+    rows = ',\n'.join(f'    uvec2(0x{x:08x}u, 0x{y:08x}u)' for x, y in map(row, range(256)))
+    return f'const uvec2 ACT[256] = uvec2[256](\n{rows}\n);'
+
+
+def main(argv):
+    if argv == ['--check']:
+        match = re.search(r'const uvec2 ACT\[256\] = uvec2\[256\]\(.*?\n\);', GLSL.read_text(), re.S)
+        if match is None or match.group(0) != declaration():
+            print(f'{GLSL} does not hold the generated table', file=sys.stderr)
+            return 1
+        return 0
+    if argv:
+        sys.exit(__doc__)
+    print(declaration())
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))