fix: harden array builder editing workflows

tests/unit/array-builder-canvas.test.js

@@ -86,6 +86,47 @@ test("Array canvas hit test는 반경 안의 가장 가까운 마이크와 채
   assertEqual(hitTestMicrophone({ x: 0, y: 0 }, arrayDefinition.microphones, viewport, 2), null, "miss");
 });
 
+test("Array canvas hit test는 viewport 변환에서 overflow된 마이크를 건너뛴다", () => {
+  const viewport = {
+    plot: { x: 0, y: 0 },
+    xMin: 0,
+    yMax: 100,
+    scale: 2,
+  };
+  const microphones = [
+    { id: "overflow", position: [Number.MAX_VALUE, 0, 0] },
+    { id: "normal", position: [5, 5, 0] },
+  ];
+  assertEqual(
+    arrayPositionToCanvas(microphones[0].position, viewport).x,
+    Infinity,
+    "fixture overflows after viewport conversion",
+  );
+  assertEqual(
+    hitTestMicrophone({ x: 10, y: 190 }, microphones, viewport, 2)?.id,
+    "normal",
+    "finite microphone remains hittable",
+  );
+});
+
+test("Array canvas fit은 극단적인 유한 좌표에서도 aperture fallback viewport를 유지한다", () => {
+  const arrayDefinition = fixture();
+  arrayDefinition.microphones[0].position = [-Number.MAX_VALUE, 0, 0];
+  arrayDefinition.microphones[1].position = [Number.MAX_VALUE, 0, 0];
+  const viewport = fitArrayViewport(800, 420, arrayDefinition);
+  for (const [name, value] of Object.entries({
+    scale: viewport.scale,
+    metersPerPixel: viewport.metersPerPixel,
+    xMin: viewport.xMin,
+    xMax: viewport.xMax,
+    yMin: viewport.yMin,
+    yMax: viewport.yMax,
+  })) {
+    assert(Number.isFinite(value), name + " remains finite");
+  }
+  assert(viewport.xMin < 0 && viewport.xMax > 0, "fallback keeps the aperture around the origin");
+});
+
 test("Array canvas grid와 keyboard nudge의 순수 helper가 1/2/5 및 y-up 규칙을 따른다", () => {
   const candidates = [niceGridStep(0.008), niceGridStep(0.08), niceGridStep(0.8), niceGridStep(8)];
   for (const step of candidates) {