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/api/news.py

@@ -0,0 +1,58 @@
+"""뉴스/공시 목록 API."""
+from __future__ import annotations
+
+from fastapi import APIRouter, HTTPException, Query
+from sqlalchemy import text
+
+from app.db.connection import get_engine
+
+router = APIRouter(prefix="/api/news", tags=["news"])
+
+
+@router.get("/{code}")
+def list_news(
+    code: str,
+    limit: int = Query(default=20, ge=1, le=200),
+    source: str | None = Query(default=None, description="naver_finance / google_rss / dart"),
+) -> dict:
+    eng = get_engine()
+    with eng.connect() as conn:
+        sym = conn.execute(
+            text("SELECT code, name FROM symbols WHERE code = :c"),
+            {"c": code},
+        ).first()
+        if not sym:
+            raise HTTPException(status_code=404, detail=f"unknown code: {code}")
+        where = "code = :c"
+        params: dict = {"c": code, "lim": limit}
+        if source:
+            where += " AND source = :src"
+            params["src"] = source
+        rows = conn.execute(
+            text(
+                f"""
+                SELECT source, published_at, title, url, sentiment_score, sentiment_label
+                  FROM news
+                 WHERE {where}
+                 ORDER BY published_at DESC
+                 LIMIT :lim
+                """
+            ),
+            params,
+        ).all()
+    return {
+        "code": sym[0],
+        "name": sym[1],
+        "count": len(rows),
+        "items": [
+            {
+                "source": r[0],
+                "published_at": r[1].isoformat() if r[1] else None,
+                "title": r[2],
+                "url": r[3],
+                "sentiment_score": float(r[4]) if r[4] is not None else None,
+                "sentiment_label": r[5],
+            }
+            for r in rows
+        ],
+    }