refactor: rename stock-lab → stock (graduation)

- git mv stock-lab/ → stock/
- docker-compose.yml: 서비스 키 + container_name + build.context +
  frontend.depends_on + agent-office STOCK_LAB_URL → STOCK_URL
- agent-office/app: config.py, service_proxy.py, agents/stock.py, tests/
  STOCK_LAB_URL → STOCK_URL
- nginx/default.conf: proxy_pass http://stock-lab → http://stock (3 lines)
- CLAUDE.md / README.md / STATUS.md / scripts/ 문구 갱신
- stock/ 내부 자기 참조 갱신

lab 네이밍 정책 (feedback_lab_naming.md) graduation.
API URL / Python import / DB 파일명 변경 없음.

stock/app/test_screener_nodes_volume_surge.py

@@ -0,0 +1,28 @@
+import datetime as dt
+import pandas as pd
+
+from app.screener.engine import ScreenContext
+from app.screener.nodes.volume_surge import VolumeSurge
+from app.screener._test_fixtures import make_master, make_prices, make_flow
+
+
+def _ctx(master, prices, flow):
+    return ScreenContext(master=master, prices=prices, flow=flow,
+                         kospi=pd.Series(dtype=float, name="kospi"),
+                         asof=dt.date(2026, 5, 12))
+
+
+def test_recent_volume_surge_gets_higher_score():
+    asof = dt.date(2026, 5, 12)
+    master = make_master(["A", "B"])
+    prices = make_prices(["A", "B"], days=30, asof=asof)
+    # A는 최근 3일 거래량 10배로
+    mask = (prices["ticker"] == "A") & (prices["date"] >= (asof - dt.timedelta(days=3)).isoformat())
+    prices.loc[mask, "volume"] *= 10
+    flow = make_flow(["A", "B"], days=30, asof=asof)
+
+    out = VolumeSurge().compute(
+        _ctx(master, prices, flow),
+        {"baseline_days": 20, "eval_days": 3},
+    )
+    assert out["A"] > out["B"]