feature: add net collector

[WRPStephanie]

新增采集网络指标的collector

[Copilot]

Pull Request Overview

This PR introduces a new network metrics collector to the host monitoring system, adding both collection logic and unit tests, and wiring it into existing input and runner components.

• Added NetCollector class for gathering network interface and TCP connection statistics.
• Extended SystemInterface (and its Linux implementation) with methods to fetch TCP and network-rate information.
• Introduced NetCollectorUnittest and updated CMake to build and run the new test.
• Registered NetCollector in input/plugin components (InputHostMonitor.cpp, HostMonitorInputRunner.cpp).

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
core/host_monitor/collector/NetCollector.h	Declared new NetCollector API
core/host_monitor/collector/NetCollector.cpp	Implemented network-stat parsing and reporting
core/host_monitor/SystemInterface.{h,cpp}	Added GetTCPStatInformation* and GetNetRateInformation*
core/host_monitor/LinuxSystemInterface.cpp	Parsed /proc/net/sockstat* and /proc/net/dev
core/unittest/host_monitor/NetCollectorUnittest.cpp	Created unit tests for NetCollector

Comments suppressed due to low confidence (1)

core/host_monitor/LinuxSystemInterface.cpp:411

• Consider adding unit tests for GetTCPStatInformationOnce and GetNetRateInformationOnce to validate parsing logic against sample /proc/net data.

bool LinuxSystemInterface::GetTCPStatInformationOnce(TCPStatInformation& tcpStatInfo) {

[Abingcbc]

没有异常情况的单测。

1. ReadSocketStat函数测试
   测试文件不存在的情况
   测试文件格式错误的情况
2. GetInterfaceConfig函数测试
   测试网络接口不存在的情况
   测试IPv4/IPv6地址解析
3. ReadNetLink函数测试
   测试netlink socket创建失败
   测试消息发送/接收失败
   测试TCP状态统计正确性
4. 网络数据解析测试
   测试/proc/net/dev文件格式变化
   测试异常数据的处理
   测试数值转换异常

[WRPStephanie]

4. /proc/net/dev文件格式变化

已补充异常情况测试。读取的/proc/net/dev的内容长期保持不变，基本可以不考虑这种情况。