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/screener/registry.py

@@ -0,0 +1,26 @@
+"""Registry of node classes (single source of truth for /nodes endpoint)."""
+
+from .nodes.hygiene      import HygieneGate
+from .nodes.foreign_buy  import ForeignBuy
+from .nodes.volume_surge import VolumeSurge
+from .nodes.momentum     import Momentum20
+from .nodes.high52w      import High52WProximity
+from .nodes.rs_rating    import RsRating
+from .nodes.ma_alignment import MaAlignment
+from .nodes.vcp_lite     import VcpLite
+from .nodes.ai_news      import AiNewsSentiment
+
+NODE_REGISTRY: dict = {
+    "foreign_buy":  ForeignBuy,
+    "volume_surge": VolumeSurge,
+    "momentum":     Momentum20,
+    "high52w":      High52WProximity,
+    "rs_rating":    RsRating,
+    "ma_alignment": MaAlignment,
+    "vcp_lite":     VcpLite,
+    "ai_news":      AiNewsSentiment,
+}
+
+GATE_REGISTRY: dict = {
+    "hygiene": HygieneGate,
+}