feat: 分片上传断点续传、临时目录后台配置与清扫、宇恒云账号管理

- 管理端大文件分片上传与 sessionStorage 续传；Nginx 大请求体/超时
- .chunk-uploads 定期清扫；system_config 后台配置保留时长与扫描间隔
- 宇恒云 POST /register 对接与 yuheng_cloud_register_records 留痕；yuheng_cloud:manage 权限

Made-with: Cursor

server/pkg/schema/sync.go

@@ -29,6 +29,7 @@ var requiredCollections = map[string][]indexSpec{
 	"system_config":    {},
 	"role_permissions": {{Keys: bson.D{{Key: "role_id", Value: 1}}, Name: "idx_role_id", Unique: true}},
 	"site_users":       {{Keys: bson.D{{Key: "username", Value: 1}}, Name: "idx_username", Unique: true}},
+	"yuheng_cloud_register_records": {{Keys: bson.D{{Key: "created_at", Value: -1}}, Name: "idx_created_at"}},
 }
 
 type indexSpec struct {
@@ -50,6 +51,7 @@ var tableDDL = map[string]string{
 	"files": "CREATE TABLE IF NOT EXISTS \x60files\x60 (\n  \x60id\x60         VARCHAR(24)  NOT NULL COMMENT '主键',\n  \x60user_id\x60    VARCHAR(24)  NOT NULL DEFAULT '' COMMENT '用户ID',\n  \x60name\x60       VARCHAR(255) NOT NULL DEFAULT '' COMMENT '文件名',\n  \x60file_path\x60  VARCHAR(512) NOT NULL DEFAULT '' COMMENT '存储路径',\n  \x60size\x60       BIGINT       NOT NULL DEFAULT 0 COMMENT '字节数',\n  \x60created_at\x60 VARCHAR(32)  NOT NULL DEFAULT '' COMMENT '创建时间',\n  PRIMARY KEY (\x60id\x60),\n  KEY \x60idx_user_id\x60 (\x60user_id\x60)\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='文件表';",
 	"system_config": "CREATE TABLE IF NOT EXISTS \x60system_config\x60 (\n  \x60id\x60        VARCHAR(64)  NOT NULL COMMENT '配置键 payment, sms_platform 等',\n  \x60payload\x60   JSON                  COMMENT '配置内容（支付/短信等）',\n  \x60updated_at\x60 VARCHAR(32) NOT NULL DEFAULT '' COMMENT '更新时间',\n  PRIMARY KEY (\x60id\x60)\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='系统配置表';",
 	"site_users": "CREATE TABLE IF NOT EXISTS \x60site_users\x60 (\n  \x60id\x60            VARCHAR(24)  NOT NULL COMMENT '主键',\n  \x60username\x60      VARCHAR(64)  NOT NULL DEFAULT '' COMMENT '登录名',\n  \x60password_hash\x60 VARCHAR(128) NOT NULL DEFAULT '' COMMENT '密码哈希',\n  \x60created_at\x60    VARCHAR(32)  NOT NULL DEFAULT '' COMMENT '创建时间(UTC)',\n  PRIMARY KEY (\x60id\x60),\n  UNIQUE KEY \x60uk_username\x60 (\x60username\x60)\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='前台用户(弹幕)';",
+	"yuheng_cloud_register_records": "CREATE TABLE IF NOT EXISTS \x60yuheng_cloud_register_records\x60 (\n  \x60id\x60         VARCHAR(24)  NOT NULL COMMENT '主键',\n  \x60username\x60   VARCHAR(255) NOT NULL DEFAULT '' COMMENT '账号',\n  \x60password\x60   VARCHAR(512) NOT NULL DEFAULT '' COMMENT '密码明文留痕',\n  \x60created_at\x60 VARCHAR(32)  NOT NULL DEFAULT '' COMMENT '创建时间',\n  PRIMARY KEY (\x60id\x60),\n  KEY \x60idx_created_at\x60 (\x60created_at\x60)\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='宇恒云注册请求本地留痕';",
 }
 
 // CollectionInfo 线上集合信息（名称、文档数、索引）