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_hygiene.py

@@ -0,0 +1,46 @@
+import datetime as dt
+
+import pandas as pd
+
+from app.screener.nodes.hygiene import HygieneGate
+from app.screener.engine import ScreenContext
+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_filter_excludes_small_cap():
+    g = HygieneGate()
+    ctx = _ctx(
+        make_master(["A", "B"], market_caps={"A": 1_000_000_000, "B": 100_000_000_000}),
+        make_prices(["A", "B"], days=30),
+        make_flow(["A", "B"], days=30),
+    )
+    out = g.filter(ctx, {**g.default_params, "min_listed_days": 0})
+    assert list(out) == ["B"]
+
+
+def test_filter_excludes_preferred():
+    g = HygieneGate()
+    ctx = _ctx(
+        make_master(["A", "B"], preferred={"B"}),
+        make_prices(["A", "B"], days=30),
+        make_flow(["A", "B"], days=30),
+    )
+    out = g.filter(ctx, {**g.default_params, "min_listed_days": 0})
+    assert list(out) == ["A"]
+
+
+def test_filter_excludes_low_value():
+    g = HygieneGate()
+    prices = make_prices(["A", "B"], days=30)
+    prices.loc[prices["ticker"] == "A", "value"] = 100_000     # 매우 작음
+    ctx = _ctx(make_master(["A", "B"]), prices, make_flow(["A", "B"], days=30))
+    out = g.filter(ctx, {**g.default_params, "min_listed_days": 0})
+    assert list(out) == ["B"]