refine: dashboard review fixes - echo removal, model escape, RMS gate, fd leak, mic cleanup

Reviewer feedback: remove AudioContext destination echo, escape model names, add RMS gate to skip silence, close mkstemp fd, clean up mic on WS close. Tests updated for the RMS gate.

tests/integration/test_api.py

@@ -147,7 +147,9 @@ class TestJobs:
         # 조회
         r = client.get(f"/v1/jobs/{job_id}", headers=headers)
         assert r.status_code == 200
-        assert r.json()["status"] == "queued"
+        body = r.json()
+        assert body["status"] == "queued"
+        assert body["source_name"] == "meeting.mp3"  # 대시보드 파일 컬럼용
 
         # 결과는 아직 없음
         r = client.get(f"/v1/jobs/{job_id}/result", headers=headers)

tests/unit/test_engine_owner.py

@@ -87,12 +87,24 @@ def test_pcm16_to_wav_header():
     assert struct.unpack("<I", wav[40:44])[0] == 16000  # data 크기
 
 
+def test_emit_hypothesis_skips_silence():
+    """무음 청크는 decode 없이 빈 가설 반환 (할루시네이션 방지)."""
+    engine = _SegFakeEngine()
+    owner = _bare_owner(engine)
+    out = owner.emit_hypothesis(b"\x00\x00" * 16000)  # 완전 무음
+    assert out["segments"] == []
+    assert engine.path is None  # decode 미실행 → 임시 파일도 안 만듦
+
+
 def test_emit_hypothesis_decodes_chunk_and_cleans_temp():
     import os
+    import random
+    import struct
 
     engine = _SegFakeEngine()
     owner = _bare_owner(engine)
-    chunk = b"\x00\x00" * 16000  # 1초 PCM16
+    # 1초 PCM16 — RMS 게이트를 통과하는 유성 신호 (무음이면 decode가 생략됨)
+    chunk = b"".join(struct.pack("<h", random.randint(-6000, 6000)) for _ in range(16000))
     out = owner.emit_hypothesis(chunk)
     assert out["audio_sec"] == 1.0
     assert len(out["segments"]) == 1