feat(phase-5): FastAPI 엔드포인트 (검색/차트/예측/메트릭/뉴스)

- GET  /api/symbols/search?q=...&seed_only=  : trigram + prefix + ILIKE 합산 정렬
- GET  /api/symbols/{code}                    : 메타
- GET  /api/chart/{code}?days=N&include_*     : OHLCV + 일별 감성 + 외인기관거래대금
- POST /api/predict/{code}?horizons=1,3,5     : on-demand 앙상블 예측 + DB 적재
                                                (user_triggered=TRUE)
- GET  /api/predict/{code}/latest             : 최신 base_date 의 예측 묶음 + base_close
                                                (UI 가 차트 마지막 점에 이어 붙임)
- GET  /api/metrics/{code}?window_days=N      : 종목 단위 hit_rate / mae (model, horizon 별)
- GET  /api/metrics?window_days=N             : 전체 누적
- GET  /api/news/{code}?source=&limit=        : 최신순 뉴스/공시 목록 (감성 점수 포함)

main.py 에 6개 라우터 모두 include.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/main.py

@@ -6,7 +6,12 @@ from contextlib import asynccontextmanager
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 
+from app.api.chart import router as chart_router
+from app.api.metrics import router as metrics_router
+from app.api.news import router as news_router
+from app.api.predict import router as predict_router
 from app.api.refresh import router as refresh_router
+from app.api.symbols import router as symbols_router
 from app.config import settings
 from app.db.connection import ping as db_ping
 from app.fetch import dart as dart_mod
@@ -41,6 +46,11 @@ app.add_middleware(
 )
 
 app.include_router(refresh_router)
+app.include_router(symbols_router)
+app.include_router(chart_router)
+app.include_router(predict_router)
+app.include_router(metrics_router)
+app.include_router(news_router)
 
 
 def _resolved_device() -> str: