feat: play moving-source acoustic timelines

assets/sample-scenes/moving-tone.scene.json

@@ -0,0 +1,32 @@
+{
+  "schemaVersion": "1.0.0",
+  "kind": "micarrsim.scene",
+  "id": "moving-tone",
+  "name": "이동하는 2 kHz 음원",
+  "description": "라이브 타임라인과 trajectory 편집을 바로 확인하는 자유음장 예제",
+  "units": "m",
+  "sampleRate": 8000,
+  "duration": 2,
+  "speedOfSound": 343,
+  "seed": 20260828,
+  "mix": { "normalization": "none", "targetPeak": 0.95 },
+  "sources": [
+    {
+      "id": "moving-source-1",
+      "name": "움직이는 2 kHz tone",
+      "position": [-0.45, -0.2, 2],
+      "trajectory": [
+        { "time": 0, "position": [-0.45, -0.2, 2] },
+        { "time": 0.5, "position": [-0.22, 0.18, 2] },
+        { "time": 1, "position": [0, 0.3, 2] },
+        { "time": 1.5, "position": [0.24, 0.12, 2] },
+        { "time": 2, "position": [0.45, -0.2, 2] }
+      ],
+      "gainDb": -6,
+      "startTime": 0,
+      "duration": 2,
+      "signal": { "type": "tone", "frequency": 2000, "phaseDeg": 0 }
+    }
+  ],
+  "ambient": []
+}