chore: OpenVINO MetricGAN GPU spike (do not merge)

Arc B580 lost the kill test: batch-14 mask p50 103 ms vs Torch CPU
70 ms enhance / OpenVINO CPU 5 ms. Production stays on known-good
CPU workers (tag known-good-cpu-2026-08-28). Hop stays 200 ms.

scripts/spike_bench_openvino.py

@@ -0,0 +1,78 @@
+#!/usr/bin/env python3
+"""OpenVINO GPU/CPU bench of MetricGAN mask ONNX (.venv-ov)."""
+from __future__ import annotations
+
+import argparse
+import statistics
+import time
+from pathlib import Path
+
+import numpy as np
+import openvino as ov
+
+
+def pct(xs, p):
+    xs = sorted(xs)
+    i = int(round((p / 100.0) * (len(xs) - 1)))
+    return xs[max(0, min(i, len(xs) - 1))]
+
+
+def bench(compiled, feats, warmup, iters):
+    infer = compiled.create_infer_request()
+    inp = compiled.inputs[0]
+    for _ in range(warmup):
+        infer.infer({inp: feats})
+    xs = []
+    for _ in range(iters):
+        t0 = time.perf_counter()
+        infer.infer({inp: feats})
+        xs.append((time.perf_counter() - t0) * 1000.0)
+    return xs
+
+
+def main() -> None:
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--onnx", default="scripts/metricgan_enhance.onnx")
+    ap.add_argument("--batch", type=int, default=14)
+    ap.add_argument("--time", type=int, default=63)
+    ap.add_argument("--feat", type=int, default=257)
+    ap.add_argument("--iters", type=int, default=40)
+    ap.add_argument("--warmup", type=int, default=10)
+    args = ap.parse_args()
+
+    core = ov.Core()
+    print("openvino", ov.__version__)
+    print("devices", core.available_devices)
+    for d in core.available_devices:
+        try:
+            print(" ", d, core.get_property(d, "FULL_DEVICE_NAME"))
+        except Exception as e:
+            print(" ", d, e)
+
+    onnx = Path(args.onnx)
+    model = ov.convert_model(str(onnx))
+    feats = np.random.randn(args.batch, args.time, args.feat).astype(np.float32)
+
+    for device in core.available_devices:
+        try:
+            compiled = core.compile_model(model, device)
+        except Exception as e:
+            print(f"compile {device} FAILED: {type(e).__name__}: {e}")
+            continue
+        try:
+            xs = bench(compiled, feats, args.warmup, args.iters)
+        except Exception as e:
+            print(f"infer {device} FAILED: {type(e).__name__}: {e}")
+            continue
+        per = [x / args.batch for x in xs]
+        print(
+            f"ov_{device} batch={args.batch} "
+            f"p50={statistics.median(xs):.2f}ms p95={pct(xs,95):.2f}ms "
+            f"p99={pct(xs,99):.2f}ms "
+            f"per_cam_p50={statistics.median(per):.2f}ms "
+            f"per_cam_p95={pct(per,95):.2f}ms"
+        )
+
+
+if __name__ == "__main__":
+    main()