security: 安全规范 + 敏感数据脱敏

- CLAUDE.md 新增安全规范章节（禁止提交 / 必须提供 .env.example）
- finance/config/settings.py 硬编码密码移除
- djapi/api/video/audioRead.py API Key 替换为占位符
- 新增 finance/.env.example 示例配置
- .gitignore 解除 .env.example 排除

Co-Authored-By: Simon <simon@doorcome.cn>

finance/config/settings.py

@@ -18,7 +18,7 @@ MARIADB_CONFIG = {
     "host": os.getenv("MAC_DB_HOST", "127.0.0.1"),
     "port": int(os.getenv("MAC_DB_PORT", "13306")),
     "user": os.getenv("MAC_DB_USER", "myquant"),
-    "password": os.getenv("MAC_DB_PASSWORD", "_H(lU1_fF*9baRTp"),
+    "password": os.getenv("MAC_DB_PASSWORD", ""),
     "database": os.getenv("MAC_DB_NAME", "myquant"),
     "charset": "utf8mb4",
     "pool_size": 5,