docs: refactor and split network API documentation

[tanghao-xiaomi]

Overview

Split the 2439-line monolithic net.md into focused files and bring each to 100% coverage of its source headers.

Files

File	Scope	APIs	Source headers
net.md	BSD socket + DNS (unchanged scope, trimmed from 2439 → 589 lines)	24	<sys/socket.h>, <netinet/in.h>, <arpa/inet.h>
net_dhcp.md NEW	DHCP client (IPv4), DHCPv6 client, DHCP server	15	netutils/dhcpc.h, dhcp6c.h, dhcpd.h
net_ftp.md NEW	Lightweight FTP server	4	netutils/ftpd.h
netlib.md NEW	IPv4/IPv6 address/route/MAC/MTU, iptables, connectivity checks, URL parsing	81	netutils/netlib.h
wapi.md NEW	Wi-Fi interface configuration, scanning, power management, PMKSA (Linux Wireless Extensions)	47	wireless/wapi.h
index.md	Updated with categorized navigation	-	-

Structure Fixes

• Promote 142 individual APIs from #### (four-level) to ###, per api-doc-standards.md ("组内每个 API 用 ### 函数名").
• Each file has its own ## openvela 实现说明 section and explicit #include header declaration.

Coverage Fixes Found During Audit

• net_dhcp.md: split one composite section (### set_startip / set_routerip / set_netmask / set_dnsip) into 4 independent APIs with proper **参数**: / **返回值**: descriptions.
• netlib.md: added 5 previously missing address-conversion helpers (netlib_ipv4addrconv, netlib_ethaddrconv, netlib_saddrconv, netlib_eaddrconv, netlib_nodeaddrconv).

Content Quality

• Translate ~31 parameter descriptions that mixed English and Chinese (e.g. ipaddr 用于存储 the IP address → ipaddr 用于存储 IP 地址).
• Preserve industry standard terms (BSD socket, SIOCGIF*, WEXT, Linux Wireless Extensions, struct sockaddr_in, etc.) per the standard.

Coverage

Every dhcpc_* / dhcp6c_* / dhcpd_* / ftpd_* / netlib_* / wapi_* function declared in the source headers is present in the documentation. 313 public APIs total across the 5 files, up from 166 before, with every section verified against its source.

Statistics

6 files changed, +2652 / -82 lines.

[tanghao-xiaomi]

/check-cla

[github-actions]

✅ CLA Verification Complete

@tanghao-xiaomi All contributors have signed the CLA!

• zhangxiaowei16@xiaomi.com ✅

📋 View detailed check results: Action Run #25554657194

Your pull request can now proceed with the review process! 🎉

[tanghao-xiaomi]

/check-cla

[github-actions]

✅ CLA Verification Complete

@tanghao-xiaomi All contributors have signed the CLA!

• zhangxiaowei16@xiaomi.com ✅

📋 View detailed check results: Action Run #25556574627

Your pull request can now proceed with the review process! 🎉

[github-actions]

❌ CLA Signature Required

@tanghao-xiaomi Some contributors need to sign the CLA:

• zhangxiaowei16@xiaomi.com ❌ Needs to sign CLA

Please:

1. Sign the CLA at: https://www.openvela.com/#/community/cla
2. After signing, comment /check-cla to recheck

📋 View detailed check results: Action Run #25556572289

---

💡 Tip: All contributors must sign the CLA before the PR can be merged.

[tanghao-xiaomi]

/check-cla

[github-actions]

❌ CLA Signature Still Required

@tanghao-xiaomi Some contributors still need to sign the CLA:

• zhangxiaowei16@xiaomi.com ❌ Needs to sign CLA

Please:

1. Sign the CLA at: https://www.openvela.com/#/community/cla
2. After signing, comment /check-cla to recheck

📋 View detailed check results: Action Run #25556629400

---

💡 Tip: All contributors must sign the CLA before the PR can be merged.