Add MicroCUDA backend, adaptive output wait, wider native K coverage (improve perf)

Shim
- Adaptive output-event wait: sleep to ~120 us before the predicted
  completion (smoothed per wait site), spin near it, back off when late.
  D4R_SHIM_OUTPUT_POLL_US restores a fixed interval.

- Defer the input-marker wait into the worker thread with VRAM interop
  (D4R_SHIM_DEFER_MARKER, default on), taking the host setup off the
  critical path.

MicroCUDA
- Experimental ZLUDA-free backend in wine_nvcuda_bridge, plus
  tools/microcuda and scripts/build_microcuda.sh. Serves accuracy, fast
  and native kernels; unregistered modules fall back to the reference
  path. Unclassified writes invalidate prepared weights.

M kernels
- SWIN_PREP_IDENTITY_AT: key weight prep by allocation identity
  (MicroCUDA); enc3 tube uses it with 8 slots. ZLUDA ignores it.

- dec2 (gfx1101): SWIN_PACKED_RESIDUAL, byte-identical, ~1.6% faster.

- Opt-in gfx12 hardware fp8 conversion (SWIN_FP8_HWCVT), unverified
  on hardware.

Native K translators
- ctile: handle variants that re-materialize the parameter base (mvlo).

- rewrite_output: check live-in registers, not just outputs.

- build.sh: native input covers all 8 flag variants, output the 4 HDR
  "max" variants; depth-tile skip stays mvhi-only.

Tools
- dump_runner and bench_dlss_kernel harness additions.

scripts/build_microcuda.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+# Experimental backend; no installation or modification of the reference path.
+# usage: build_microcuda.sh [OUTPUT_DIR]
+# Modules come from a pack made separately with tools/microcuda/make_pack.py (D4R_MICROCUDA_PACK at run time).
+set -euo pipefail
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+[[ $# -le 1 ]] || { echo "usage: $0 [OUTPUT_DIR]" >&2; exit 2; }
+rocm="${D4R_ROCM_DIR:-/opt/rocm}"
+out="$(realpath -m "${1:-$root/build/microcuda}")"
+mkdir -p "$out"
+"${CXX:-g++}" -std=c++20 -O2 -fPIC -shared -Wall -Wextra -Werror -Wno-deprecated-declarations \
+  -I"$rocm/include" "$root/tools/microcuda/runtime.cpp" \
+  -L"$rocm/lib" -Wl,-rpath,"$rocm/lib" -lamdhip64 -lcrypto -lpthread \
+  -Wl,-z,defs -Wl,-soname,libd4r_microcuda.so -o "$out/libd4r_microcuda.so"
+echo "Built $out/libd4r_microcuda.so (opt-in; modules from a make_pack.py pack)"