improve: implied_rsi 계수 4.0→2.0으로 완화 — 포화 임계점 12.5%→25% (#181)

SmartScanner의 implied_rsi 공식에서 계수를 4.0에서 2.0으로 수정.
12.5% 이상 변동률에서 RSI=100으로 포화되던 문제를 개선.

변경 전: 50 + (change_rate * 4.0) → 12.5% 변동 시 RSI=100
변경 후: 50 + (change_rate * 2.0) → 25% 변동 시 RSI=100

이제 10% 상승 → RSI=70, 12.5% 상승 → RSI=75 (의미 있는 구분 가능)
해외 소형주(NYSE American 등)의 RSI=100 집단 현상 완화.

- smart_scanner.py 3곳 동일 공식 모두 수정
- TestImpliedRSIFormula 클래스 5개 테스트 추가

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

src/analysis/smart_scanner.py

@@ -175,7 +175,7 @@ class SmartVolatilityScanner:
                 liquidity_score = volume_rank_bonus.get(stock_code, 0.0)
                 score = min(100.0, volatility_score + liquidity_score)
                 signal = "momentum" if change_rate >= 0 else "oversold"
-                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 4.0)))
+                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 2.0)))
 
                 candidates.append(
                     ScanCandidate(
@@ -282,7 +282,7 @@ class SmartVolatilityScanner:
             liquidity_score = volume_rank_bonus.get(stock_code, 0.0)
             score = min(100.0, volatility_score + liquidity_score)
             signal = "momentum" if change_rate >= 0 else "oversold"
-            implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 4.0)))
+            implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 2.0)))
             candidates.append(
                 ScanCandidate(
                     stock_code=stock_code,
@@ -338,7 +338,7 @@ class SmartVolatilityScanner:
 
                 score = min(volatility_pct / 10.0, 1.0) * 100.0
                 signal = "momentum" if change_rate >= 0 else "oversold"
-                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 4.0)))
+                implied_rsi = max(0.0, min(100.0, 50.0 + (change_rate * 2.0)))
                 candidates.append(
                     ScanCandidate(
                         stock_code=stock_code,

src/main.py

@@ -1358,10 +1358,18 @@ 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)
@@ -1372,7 +1380,7 @@ 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
+
+
 # ---------------------------------------------------------------------------
 # BUY cooldown tests (#179)
 # ---------------------------------------------------------------------------

tests/test_smart_scanner.py

@@ -350,6 +350,42 @@ class TestSmartVolatilityScanner:
         assert [c.stock_code for c in candidates] == ["ABCD"]
 
 
+class TestImpliedRSIFormula:
+    """Test the implied_rsi formula in SmartVolatilityScanner (issue #181)."""
+
+    def test_neutral_change_gives_neutral_rsi(self) -> None:
+        """0% change → implied_rsi = 50 (neutral)."""
+        # formula: 50 + (change_rate * 2.0)
+        rsi = max(0.0, min(100.0, 50.0 + (0.0 * 2.0)))
+        assert rsi == 50.0
+
+    def test_10pct_change_gives_rsi_70(self) -> None:
+        """10% upward change → implied_rsi = 70 (momentum signal)."""
+        rsi = max(0.0, min(100.0, 50.0 + (10.0 * 2.0)))
+        assert rsi == 70.0
+
+    def test_minus_10pct_gives_rsi_30(self) -> None:
+        """-10% change → implied_rsi = 30 (oversold signal)."""
+        rsi = max(0.0, min(100.0, 50.0 + (-10.0 * 2.0)))
+        assert rsi == 30.0
+
+    def test_saturation_at_25pct(self) -> None:
+        """Saturation occurs at >=25% change (not 12.5% as with old coefficient 4.0)."""
+        rsi_12pct = max(0.0, min(100.0, 50.0 + (12.5 * 2.0)))
+        rsi_25pct = max(0.0, min(100.0, 50.0 + (25.0 * 2.0)))
+        rsi_30pct = max(0.0, min(100.0, 50.0 + (30.0 * 2.0)))
+        # At 12.5% change: RSI = 75 (not 100, unlike old formula)
+        assert rsi_12pct == 75.0
+        # At 25%+ saturation
+        assert rsi_25pct == 100.0
+        assert rsi_30pct == 100.0  # Capped
+
+    def test_negative_saturation(self) -> None:
+        """Saturation at -25% gives RSI = 0."""
+        rsi = max(0.0, min(100.0, 50.0 + (-25.0 * 2.0)))
+        assert rsi == 0.0
+
+
 class TestRSICalculation:
     """Test RSI calculation in VolatilityAnalyzer."""