fix(server): different graph name share the same backend

[JisoLya]

Purpose of the PR

• close hugegraph-server 启动不正常，查看日志有报错 #3007

During backend initialization, the server creates two graphs — ~sys_graph and hugegraph (default) — that share the same store backend. This leads to a key collision:

• ~sys_graph writes server node info with id server-1
• ~sys_graph reads back server-1 successfully
• hugegraph writes server node info with the same id server-1
• hugegraph reads from the shared table — retrieves ~sys_graph's record instead → type mismatch → parse error

Main Changes

Change ServerInfoManager.selfNodeId() which returns "server-1" previously to "{graphname}/server-1"

Verifying these changes

• Trivial rework / code cleanup without any test coverage. (No Need)
• Already covered by existing tests, such as (please modify tests here).
• Need tests and can be verified as follows:
  • xxx

Does this PR potentially affect the following parts?

• Dependencies (add/update license info & regenerate_known_dependencies.sh)
• Modify configurations
• The public API
• Other affects (typed here)
• Nope

Documentation Status

• Doc - TODO
• Doc - Done
• Doc - No Need

[imbajin]

修复方向正确，用图命名空间前缀隔离 server ID 能解决跨图 key 碰撞问题。但存在一个阻塞性逻辑缺陷 + 测试缺失，建议修复后再合并。

---

‼️ 测试覆盖不足（阻塞）

PR 勾选了"已有测试覆盖"，但全量搜索 hugegraph-server/hugegraph-test/ 后，没有任何测试覆盖"两图共享同一 backend + 相同 nodeId"的场景。

建议补充回归测试，至少验证：

1. ~sys_graph 和 hugegraph 使用相同 nodeId（如 "server-1"）初始化时，selfNodeId() 返回值互不相同
2. 两个图能并发启动，不抛出 parse error 或 "already in cluster" 异常

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⚠️ 升级兼容性说明缺失

存量部署 backend 中的 ServerInfo vertex key 格式为 server-1；升级后代码改为以 DEFAULT-hugegraph/server-1 查询，旧记录查不到便重新写入新记录，旧的 server-1 记录以孤儿形式留在 backend 中不被清理。对功能影响有限，但建议在 PR 描述或 Release Notes 中注明，避免运维困惑。

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🧹 小建议：spaceGraphName 字符集

spaceGraphName() 的值由用户配置拼接而来，没有对 / 字符的校验。若用户将 graphSpace 配置为含 / 的字符串，生成的 ID 会出现多个 /，可能引发后续解析歧义。建议加一行断言或在文档中说明 graphSpace 不允许包含 /。

[imbajin]

‼️ Critical：initServerInfo() 中读写路径 ID 不一致（阻塞性问题）

此处修改后 selfNodeId() 返回命名空间化的 ID（如 DEFAULT-hugegraph/server-1），但调用方 initServerInfo() 的存在性检查仍使用原始裸 ID，两条路径的 key 不同：

// initServerInfo()（本 PR 未修改这部分）
Id serverId = nodeInfo.nodeId();                        // ❌ 裸 ID："server-1"
HugeServerInfo existed = this.serverInfo(serverId);    // ❌ 用 "server-1" 查询
// ...
this.globalNodeInfo = nodeInfo;                        // line 140，赋值后 selfNodeId() 才变
this.saveServerInfo(this.selfNodeId(), ...);            // ✅ 保存 "DEFAULT-hugegraph/server-1"

后果：

• lines 109–122 的 alive 检查（防止同名节点重复启动的保护）永远查不到已命名空间化的旧记录，保护逻辑被静默跳过
• 重启时旧的命名空间记录不会被正确识别，会直接写入新记录，旧记录成为孤儿数据积累在 backend 中

建议修法： 在 initServerInfo() 入口先设置 globalNodeInfo，再统一用 selfNodeId() 做后续查询，保持读写 key 一致：

public synchronized void initServerInfo(GlobalMasterInfo nodeInfo) {
    E.checkArgument(nodeInfo != null, "The global node info can't be null");
    this.globalNodeInfo = nodeInfo;   // 先赋值，selfNodeId() 立即返回命名空间 ID
    Id serverId = this.selfNodeId();  // ✅ 与 save / remove 路径使用同一个 key
    HugeServerInfo existed = this.serverInfo(serverId);
    if (existed != null && existed.alive()) {
        // ... 存活检查 & 等待逻辑不变 ...
    }
    E.checkArgument(existed == null || !existed.alive(),
                    "The server with name '%s' already in cluster", serverId);
    // master 唯一性检查不变 ...
    this.saveServerInfo(serverId, this.selfNodeRole());
}

这样读取和写入始终使用同一个 ID，alive 检查和 master 唯一性保护才能真正生效。

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.25%. Comparing base (e108076) to head (b4ede79).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@              Coverage Diff              @@
##             master    #3027       +/-   ##
=============================================
+ Coverage     35.85%   93.25%   +57.40%     
+ Complexity      338       65      -273     
=============================================
  Files           802        9      -793     
  Lines         67995      267    -67728     
  Branches       8902       22     -8880     
=============================================
- Hits          24381      249    -24132     
+ Misses        41008        8    -41000     
+ Partials       2606       10     -2596     

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