```

feat(base): 添加邮箱注册码功能及用户注册接口

- 在 `sessionManager` 中新增邮件注册码缓存管理实例和相关方法
- 实现生成、保存、验证、删除邮件注册码的逻辑
- 新增 `/reg` 和 `/email` 接口用于用户注册和发送验证码
- 引入 `golang-lru` 依赖以支持限流缓存功能
- 调整包导入顺序，优化代码结构
```

common/utils/golang-lru-main/doc.go

@@ -0,0 +1,24 @@
+// Copyright IBM Corp. 2014, 2025
+// SPDX-License-Identifier: MPL-2.0
+
+// Package lru provides three different LRU caches of varying sophistication.
+//
+// Cache is a simple LRU cache. It is based on the LRU implementation in
+// groupcache: https://github.com/golang/groupcache/tree/master/lru
+//
+// TwoQueueCache tracks frequently used and recently used entries separately.
+// This avoids a burst of accesses from taking out frequently used entries, at
+// the cost of about 2x computational overhead and some extra bookkeeping.
+//
+// ARCCache is an adaptive replacement cache. It tracks recent evictions as well
+// as recent usage in both the frequent and recent caches. Its computational
+// overhead is comparable to TwoQueueCache, but the memory overhead is linear
+// with the size of the cache.
+//
+// ARC has been patented by IBM, so do not use it if that is problematic for
+// your program. For this reason, it is in a separate go module contained within
+// this repository.
+//
+// All caches in this package take locks while operating, and are therefore
+// thread-safe for consumers.
+package lru