feat: add WebGPU DAS backend

tests/integration/cpu-baseline.test.js

@@ -30,5 +30,13 @@ test("192채널 · 50×50 CPU baseline이 ground truth를 찾는다", async () =
   assertEqual(result.pointCount, 2500, "scan point count");
   assert(localizationError < 0.03, `localization error=${localizationError} m`);
   assert(Number.isFinite(result.bands[0].peak.rawPower) && result.bands[0].peak.rawPower > 0, "finite peak power");
+  globalThis.__micarrsimCpuBaseline = {
+    channels: synthesis.channels,
+    sampleRate: synthesis.sampleRate,
+    arrayDefinition,
+    scene,
+    experiment,
+    result,
+  };
   document.documentElement.dataset.cpuBaselineMs = elapsedMs.toFixed(1);
 });