fix: uvicorn 미설치 시 dashboard 실패를 동기적으로 감지하여 오해 없는 로그 출력 (#178)

스레드 시작 전에 uvicorn import를 검증하도록 _start_dashboard_server 수정.
uvicorn 미설치 시 "started" 로그 없이 즉시 WARNING 출력 후 None 반환.

- 사전 import 검증으로 "started" → "failed" 오해 소지 있는 로그 쌍 제거
- uvicorn 미설치 시 명확한 경고 메시지 출력
- test_start_dashboard_server_returns_none_when_uvicorn_missing 테스트 추가

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/main.py

@@ -1300,10 +1300,18 @@ def _start_dashboard_server(settings: Settings) -> threading.Thread | None:
     if not settings.DASHBOARD_ENABLED:
         return None
 
+    # Validate dependencies before spawning the thread so startup failures are
+    # reported synchronously (avoids the misleading "started" → "failed" log pair).
+    try:
+        import uvicorn  # noqa: F401
+        from src.dashboard import create_dashboard_app  # noqa: F401
+    except ImportError as exc:
+        logger.warning("Dashboard server unavailable (missing dependency): %s", exc)
+        return None
+
     def _serve() -> None:
         try:
             import uvicorn
-
             from src.dashboard import create_dashboard_app
 
             app = create_dashboard_app(settings.DB_PATH)
@@ -1314,7 +1322,7 @@ def _start_dashboard_server(settings: Settings) -> threading.Thread | None:
                 log_level="info",
             )
         except Exception as exc:
-            logger.warning("Dashboard server failed to start: %s", exc)
+            logger.warning("Dashboard server stopped unexpectedly: %s", exc)
 
     thread = threading.Thread(
         target=_serve,

tests/test_main.py

@@ -2194,6 +2194,29 @@ def test_start_dashboard_server_enabled_starts_thread() -> None:
     mock_thread.start.assert_called_once()
 
 
+def test_start_dashboard_server_returns_none_when_uvicorn_missing() -> None:
+    """Returns None (no thread) and logs a warning when uvicorn is not installed."""
+    settings = Settings(
+        KIS_APP_KEY="test_key",
+        KIS_APP_SECRET="test_secret",
+        KIS_ACCOUNT_NO="12345678-01",
+        GEMINI_API_KEY="test_gemini_key",
+        DASHBOARD_ENABLED=True,
+    )
+    import builtins
+    real_import = builtins.__import__
+
+    def mock_import(name: str, *args: object, **kwargs: object) -> object:
+        if name == "uvicorn":
+            raise ImportError("No module named 'uvicorn'")
+        return real_import(name, *args, **kwargs)
+
+    with patch("builtins.__import__", side_effect=mock_import):
+        thread = _start_dashboard_server(settings)
+
+    assert thread is None
+
+
 # ---------------------------------------------------------------------------
 # market_outlook BUY confidence threshold tests (#173)
 # ---------------------------------------------------------------------------