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.

docker-compose.yml

@@ -22,12 +22,12 @@ services:
       timeout: 5s
       retries: 3
 
-  stock-lab:
+  stock:
     build:
-      context: ./stock-lab
+      context: ./stock
       args:
         APP_VERSION: ${APP_VERSION:-dev}
-    container_name: stock-lab
+    container_name: stock
     restart: unless-stopped
     ports:
       - "18500:8000"
@@ -136,7 +136,7 @@ services:
     environment:
       - TZ=${TZ:-Asia/Seoul}
       - CORS_ALLOW_ORIGINS=${CORS_ALLOW_ORIGINS:-http://localhost:3007,http://localhost:8080}
-      - STOCK_LAB_URL=http://stock-lab:8000
+      - STOCK_URL=http://stock:8000
       - MUSIC_LAB_URL=http://music-lab:8000
       - BLOG_LAB_URL=http://blog-lab:8000
       - REALESTATE_LAB_URL=http://realestate-lab:8000
@@ -157,7 +157,7 @@ services:
     volumes:
       - ${RUNTIME_PATH:-.}/data/agent-office:/app/data
     depends_on:
-      - stock-lab
+      - stock
       - music-lab
       - blog-lab
       - realestate-lab
@@ -242,7 +242,7 @@ services:
     restart: unless-stopped
     depends_on:
       - lotto
-      - stock-lab
+      - stock
       - music-lab
       - blog-lab
       - realestate-lab