Add SRV DNS resolution for multiplayer server addresses

[Copilot]

Enables users to connect to multiplayer servers using domain names only (e.g., example.com) instead of requiring explicit host:port format. Client queries _phira._tcp.<domain> SRV records to resolve target host and port.

Implementation

• SRV resolver module (srv_resolver.rs)

  • Queries DNS SRV records with _phira._tcp. prefix
  • Singleton Lazy<TokioAsyncResolver> for efficiency
  • Port detection logic distinguishes IPv4/IPv6 with ports from bare addresses
  • Returns addresses with explicit ports unchanged (backwards compatible)

• Port detection logic

  • example.com:12345 → pass-through
  • [::1]:8080 → pass-through (IPv6 with port)
  • example.com → SRV lookup
  • ::1 → SRV lookup (bare IPv6 detected by multiple colons before last colon)

• Connection updates

  • phira/src/mp/panel.rs: Added resolve_server_address() before TcpStream::connect()
  • phira-monitor/src/scene.rs: Same pattern for monitor application

Dependencies

• trust-dns-resolver 0.23.2 - SRV record queries
• once_cell 1.21.3 - Singleton resolver instance

Example Usage

Server administrator configures DNS:

_phira._tcp.example.com. 86400 IN SRV 0 5 12345 game-server.example.com.

User connects with just example.com → client resolves to game-server.example.com:12345

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• 8.8.4.4
  • Triggering command: REDACTED, pid is -1 (packet block)
• 8.8.8.8
  • Triggering command: REDACTED, pid is -1 (packet block)
• esm.ubuntu.com
  • Triggering command: /usr/lib/apt/methods/https /usr/lib/apt/methods/https --emit=dep-info,metadata -C opt-level=2 -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --check-cfg cfg(docsrs,test) stup�� in.so /lto-wrapper bin/rustc 6detect_compiler/home/REDACTED/.rustup/toolchains/stable-x86_64-REDACTED-linux-gnu/bin/rustc stup/toolchains/--crate-name stup/toolchains/rustc_hash bin/rustc (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>标题：支持 SRV DNS 解析以允许在联机服务器地址中省略端口号</issue_title>
<issue_description>描述：
当前在设置联机服务器地址时必须明确指定主机和端口（例如 example.com:12345）。建议在解析地址时加入 SRV（DNS Service）解析支持，允许用户只填写域名（例如 example.com），客户端通过 SRV 记录获取实际的目标主机和端口，从而简化配置并兼容使用 SRV 的托管/代理方案。

动机：

• 提升用户体验：用户只需填写域名，无需记住或填写端口号。
• 便于服务迁移与负载均衡：服务端可通过 SRV 指向不同主机和端口，而无需强制用户更改客户端设置。
• 降低配置错误：对使用自定义端口或反向代理的部署更友好。

建议实现（行为规范）：

1. 当用户输入的服务器地址未包含端口（无 ":" 及端口号）时，尝试进行 SRV 查询。
2. 默认 SRV 前缀建议为 _phira._tcp.，并将该前缀作为可配置项以支持其它部署约定。
3. 若 SRV 查询成功且返回记录，按 SRV 的 target:port 使用解析到的主机和端口进行连接；应遵循 SRV 的优先级与权重规则（至少实现优先级排序，针对相同优先级可按权重或随机选择）。
4. 若 SRV 查询失败（无记录或查询超时/错误），回退到现有行为（使用默认端口或用户显式指定的端口）。显式指定端口应始终优先于 SRV 解析结果。
5. 为避免阻塞与感知延迟，应设定合理的 SRV 查询超时时间与缓存策略（例如短期缓存、异步解析或在 UI 上提示“正在解析地址”）。

示例：

• 用户输入：example.com
  • 客户端查询 _phira._tcp.example.com 的 SRV 记录，若返回 target=myserver.example.net port=26666，则连接 myserver.example.net:26666。
• 用户输入：example.com:25566
  • 直接使用指定的端口，不进行 SRV 查询（显式端口优先）。

验收条件：

• 在无端口的地址输入场景下，可成功解析并连接到通过 SRV 指定的主机与端口（含优先级/权重处理或明确说明实现策略）。
• 当 SRV 不存在或解析失败时，行为回退并与当前版本一致（不影响已有配置）。
• 明确显式端口优先于 SRV。
• 提供单元/集成测试覆盖：成功 SRV 解析、无 SRV 回退、SRV 多记录的优先级/权重处理、超时与错误处理。
  </issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes 标题：支持 SRV DNS 解析以允许在联机服务器地址中省略端口号 #638

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