perf: harden realtime localization pipeline

tests/unit/webgpu.test.js

@@ -109,6 +109,31 @@ test("WebGPU STFT packing이 microphone 주파수 응답을 bin별로 역보정
   });
   assertEqual(uncompensated[0], 0, "disabled compensation real");
   assertEqual(uncompensated[1], 2, "disabled compensation imaginary");
+
+  const notchedMicrophones = [{
+    frequencyResponse: [
+      { frequencyHz: 0, gainDb: -120 },
+      { frequencyHz: 4000, gainDb: -120 },
+    ],
+  }];
+  const notched = {
+    frameCount: 1,
+    microphoneCount: 1,
+    spectra: new Map([[8, { real: Float32Array.of(1), imaginary: Float32Array.of(0) }]]),
+  };
+  const limited = packStftBatch(notched, [8], {
+    microphones: notchedMicrophones,
+    sampleRate: 8000,
+    fftSize: 256,
+  });
+  const explicitLegacyLimit = packStftBatch(notched, [8], {
+    microphones: notchedMicrophones,
+    sampleRate: 8000,
+    fftSize: 256,
+    maxCompensationDb: 120,
+  });
+  assertNear(limited[0], 10 ** (24 / 20), 1e-5, "default notch boost limit");
+  assert(explicitLegacyLimit[0] > 999_000, "explicit 120 dB notch boost");
 });
 
 test("WebGPU batch size가 storage, dispatch, memory 한도를 모두 지킨다", () => {