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_position_sizer.py

@@ -0,0 +1,33 @@
+import datetime as dt
+import pandas as pd
+
+from app.screener.engine import ScreenContext
+from app.screener.position_sizer import compute_atr_wilder, plan_positions
+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_atr_wilder_positive_and_smooth():
+    df = make_prices(["A"], days=30)
+    atr = compute_atr_wilder(df[df["ticker"] == "A"], window=14)
+    assert atr > 0
+
+
+def test_plan_positions_returns_entry_stop_target():
+    asof = dt.date(2026, 5, 12)
+    master = make_master(["A"])
+    prices = make_prices(["A"], days=30, asof=asof, start_close=50000)
+    flow = make_flow(["A"], days=30, asof=asof)
+    ctx = _ctx(master, prices, flow)
+    sizing = plan_positions(ctx, ["A"], {"atr_window": 14, "atr_stop_mult": 2.0, "rr_ratio": 2.0})
+
+    row = sizing["A"]
+    assert row["entry_price"] > 0
+    assert row["stop_price"] < row["entry_price"]
+    assert row["target_price"] > row["entry_price"]
+    assert row["atr14"] > 0