OBV 신호선 점선 처리로 본선과 시각 구분 보장

- 진단 로그로 두 시리즈가 정상 생성됨을 확인 (series:2, visible:true, color:#2196F3)
- 미니차트는 800봉 누적 OBV 계산 → 마지막 200봉 구간에서 OBV와 SMA(9)가 수렴,
  주황 신호선이 파란 본선을 덮어 1개 선처럼 보이는 것이 원인
- registry plot1에 lineStyle:'dashed' 추가
- normalizeSignalLineIndicatorPlots OBV 분기에서 plot0=solid, plot1=dashed 강제

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/utils/indicatorRegistry.ts

@@ -349,7 +349,7 @@ export const INDICATOR_REGISTRY: IndicatorDef[] = [
   { type:'HistoricalVolatility',name:'Historical Volatility',    koreanName:'역사적변동성',    shortName:'HV',     category:'Volatility', overlay:false, defaultParams:{length:20, annualBars:252},               plots:[{id:'plot0',title:'HV',   color:'#E91E63',type:'line',lineWidth:2}],                                                                                         description:'역사적 변동성 (연화)' },
 
   // ── Volume ────────────────────────────────────────────────────────────────
-  { type:'OBV',                 name:'On Balance Volume',          koreanName:'잔량균형지수',        shortName:'OBV',   category:'Volume', overlay:false, defaultParams:{maType:'SMA', maLength:9},                      plots:[{id:'plot0',title:'OBV',  color:'#2196F3',type:'line',lineWidth:2},{id:'plot1',title:'Signal',color:'#FF9800',type:'line',lineWidth:1}], hlines:[], description:'잔량 균형 지수 (OBV + 이동평균 신호선)' },
+  { type:'OBV',                 name:'On Balance Volume',          koreanName:'잔량균형지수',        shortName:'OBV',   category:'Volume', overlay:false, defaultParams:{maType:'SMA', maLength:9},                      plots:[{id:'plot0',title:'OBV',  color:'#2196F3',type:'line',lineWidth:2},{id:'plot1',title:'Signal',color:'#FF9800',type:'line',lineWidth:1,lineStyle:'dashed'}], hlines:[], description:'잔량 균형 지수 (OBV + 이동평균 신호선)' },
   { type:'VR',                  name:'Volume Ratio',               koreanName:'거래량비율',          shortName:'VR',    category:'Volume', overlay:false, defaultParams:{length:10},                                 plots:[{id:'plot0',title:'VR',   color:'#AB47BC',type:'line',lineWidth:2}],                                  hlines:[{price:200,color:'#EF5350'},{price:100,color:'#607D8B'},{price:50,color:'#4CAF50'}], description:'거래량 비율 (VR)' },
   { type:'Disparity',           name:'Disparity Index',            koreanName:'이격도',              shortName:'Disp',  category:'Oscillators', overlay:false, defaultParams:{ultraLength:5, shortLength:10, midLength:20, longLength:60, src:'close'}, plots:[{id:'plot0',title:'초단기',color:'#E91E63',type:'line',lineWidth:1},{id:'plot1',title:'단기',color:'#FF9800',type:'line',lineWidth:1},{id:'plot2',title:'중기',color:'#4CAF50',type:'line',lineWidth:1},{id:'plot3',title:'장기',color:'#2196F3',type:'line',lineWidth:1}], hlines:[{price:100,color:'#607D8B'}], description:'이격도 (종가÷이평×100)' },
   { type:'Psychological',       name:'Psychological Line',         koreanName:'심리도',              shortName:'Psy',   category:'Oscillators', overlay:false, defaultParams:{length:12},                                 plots:[{id:'plot0',title:'심리도',color:'#00BCD4',type:'line',lineWidth:2}],                              hlines:[{price:75,color:'#EF5350',label:'과열선'},{price:50,color:'#607D8B',label:'중앙선'},{price:25,color:'#4CAF50',label:'침체선'}], description:'심리도 (상승일 비율)' },
@@ -481,6 +481,14 @@ function normalizeSignalLineIndicatorPlots(
           type: 'line' as const,
           color: reg.color,
           lineWidth: Math.max(2, normalized.lineWidth ?? reg.lineWidth ?? 2),
+          lineStyle: 'solid' as const,
+        };
+      }
+      // OBV 신호선 — 값이 본선과 거의 같더라도 점선으로 시각적 구분 보장
+      if (p.id === 'plot1') {
+        return {
+          ...normalized,
+          lineStyle: 'dashed' as const,
         };
       }
       return normalized;