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/rr/spv_exact_convert.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+"""Decorate every float conversion of a SPIR-V module NoContraction, so the driver keeps it.
+
+usage: spv_exact_convert.py IN.spv [OUT.spv]
+
+RADV folds float(float16_t(x)) back to x unless the conversions are marked exact; glslang's `precise` does not reach
+conversions. With the decoration a binary16 rounding is two instructions (engine/rr/rr_exact.glsl, RR_EXACT_CONVERT)
+instead of three with an opaque zero OR-ed into the bits.
+"""
+import struct
+import sys
+
+OP_DECORATE, OP_FCONVERT, NO_CONTRACTION = 71, 115, 42
+
+
+def main():
+    src = sys.argv[1]
+    dst = sys.argv[2] if len(sys.argv) > 2 else src
+    data = open(src, 'rb').read()
+    words = list(struct.unpack(f'<{len(data) // 4}I', data))
+    if words[0] != 0x07230203:
+        sys.exit(f'{src}: not SPIR-V')
+    insts, i = [], 5
+    while i < len(words):
+        count = words[i] >> 16
+        insts.append((words[i] & 0xffff, words[i:i + count]))
+        i += count
+    ids = [w[2] for op, w in insts if op == OP_FCONVERT]
+    first_type = next(k for k, (op, _) in enumerate(insts) if 19 <= op <= 39)   # annotations end where types begin
+    out = list(words[:5])
+    for k, (op, w) in enumerate(insts):
+        if k == first_type:
+            for result in ids:
+                out += [3 << 16 | OP_DECORATE, result, NO_CONTRACTION]
+        out += w
+    open(dst, 'wb').write(struct.pack(f'<{len(out)}I', *out))
+    print(f'{dst}: {len(ids)} conversions marked exact')
+
+
+if __name__ == '__main__':
+    main()