feat(stock-webai): /api/webai/news-sentiment daily dump

JOINs news_sentiment with krx_master for name fallback. Sorted by
score DESC. Date param defaults to latest. Empty table returns
{date: null, count: 0, items: []}. 4 integration tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

stock/app/test_webai_endpoints.py

@@ -87,3 +87,87 @@ def test_webai_portfolio_missing_key_returns_401(client):
     r = client.get("/api/webai/portfolio")
     assert r.status_code == 401
     assert "X-WebAI-Key" in r.json()["detail"]
+
+
+def _seed_news_sentiment(date_str: str, rows: list[tuple]):
+    """rows: list of (ticker, score_raw, reason, news_count)."""
+    db_path = os.environ["STOCK_DB_PATH"]
+    c = sqlite3.connect(db_path)
+    for ticker, score, reason, news_count in rows:
+        c.execute(
+            "INSERT OR REPLACE INTO news_sentiment "
+            "(ticker, date, score_raw, reason, news_count, source) "
+            "VALUES (?, ?, ?, ?, ?, 'articles')",
+            (ticker, date_str, score, reason, news_count)
+        )
+    c.commit()
+    c.close()
+
+
+def _seed_krx_master(rows: list[tuple]):
+    """rows: list of (ticker, name)."""
+    db_path = os.environ["STOCK_DB_PATH"]
+    c = sqlite3.connect(db_path)
+    import datetime as dt
+    now = dt.datetime.utcnow().isoformat()
+    for ticker, name in rows:
+        c.execute(
+            "INSERT OR REPLACE INTO krx_master "
+            "(ticker, name, market, market_cap, updated_at) VALUES (?, ?, 'KOSPI', 0, ?)",
+            (ticker, name, now)
+        )
+    c.commit()
+    c.close()
+
+
+def test_webai_news_sentiment_returns_latest_date_when_no_param(client):
+    _seed_krx_master([("005930", "삼성전자"), ("000660", "SK하이닉스")])
+    _seed_news_sentiment("2026-05-14", [("005930", 5.0, "old", 5)])
+    _seed_news_sentiment("2026-05-15", [
+        ("005930", 6.2, "HBM 양산 가시화", 12),
+        ("000660", 5.5, "PPI 우려에도 강세", 8),
+    ])
+
+    r = client.get("/api/webai/news-sentiment", headers=HEADERS_OK)
+    assert r.status_code == 200
+    body = r.json()
+    assert body["date"] == "2026-05-15"
+    assert body["count"] == 2
+    # sorted by score DESC
+    assert body["items"][0]["ticker"] == "005930"
+    assert body["items"][0]["score"] == 6.2
+    assert body["items"][0]["name"] == "삼성전자"
+    assert body["items"][0]["reason"] == "HBM 양산 가시화"
+
+
+def test_webai_news_sentiment_filters_by_date_param(client):
+    _seed_krx_master([("005930", "삼성전자")])
+    _seed_news_sentiment("2026-05-14", [("005930", 5.0, "yesterday", 5)])
+    _seed_news_sentiment("2026-05-15", [("005930", 6.2, "today", 12)])
+
+    r = client.get("/api/webai/news-sentiment?date=2026-05-14", headers=HEADERS_OK)
+    body = r.json()
+    assert body["date"] == "2026-05-14"
+    assert body["count"] == 1
+    assert body["items"][0]["reason"] == "yesterday"
+
+
+def test_webai_news_sentiment_empty_table_returns_count_zero(client):
+    r = client.get("/api/webai/news-sentiment", headers=HEADERS_OK)
+    body = r.json()
+    assert body["date"] is None
+    assert body["count"] == 0
+    assert body["items"] == []
+
+
+def test_webai_news_sentiment_items_sorted_by_score_desc(client):
+    _seed_krx_master([("A", "A주"), ("B", "B주"), ("C", "C주")])
+    _seed_news_sentiment("2026-05-15", [
+        ("A", 1.0, "low", 1),
+        ("B", 9.0, "high", 1),
+        ("C", 5.0, "mid", 1),
+    ])
+
+    r = client.get("/api/webai/news-sentiment", headers=HEADERS_OK)
+    items = r.json()["items"]
+    assert [i["score"] for i in items] == [9.0, 5.0, 1.0]