feat: 后端全量更新 - 含所有本次需求

- Contract.php: 返回合约账户余额(balance_contract)
- My.php: 地址管理增加BTC/ETH
- AppContract.php: 一键平仓(closeall)
- AppProxy.php: 代理专属注册链接 + 分级权限(L1/L2)
- site.php: 手续费减半(0.018→0.009)
- agent_permission_setup.sql: 代理权限SQL
- crypto_news_crawler.py: 新闻自动采集脚本

public/assets/libs/Sortable/.circleci/config.yml

@@ -0,0 +1,33 @@
+version: 2.0
+jobs:
+  build:
+    docker:
+      - image: circleci/node:10.16-browsers
+    steps:
+      - checkout
+
+      - restore_cache:
+          keys:
+          - v1-dependencies-{{ checksum "package.json" }}
+          - v1-dependencies-
+
+      - run: npm install
+
+      - save_cache:
+          paths:
+            - node_modules
+          key: v1-dependencies-{{ checksum "package.json" }}
+
+      - run: npm run build:umd
+
+      - run:
+          name: Compatibility Test
+          command: |
+            if [ -z "$CIRCLE_PR_NUMBER" ];
+            then
+              npm run test:compat
+            fi
+      - run: npm run test
+
+      - store_test_results:
+          path: /tmp/test-results