feat(v2ex): add node, user, member, replies, nodes commands

[Astro-Han]

Description

Add 5 new public API commands to the V2EX adapter, utilizing previously unused V1 API endpoints. All commands are strategy: public + browser: false — no login or browser required.

Command	API Endpoint	Description
v2ex node <name>	/api/topics/show.json?node_name=	Browse topics by node
v2ex user <username>	/api/topics/show.json?username=	List topics by user
v2ex member <username>	/api/members/show.json?username=	User profile
v2ex replies <id>	/api/replies/show.json?topic_id=	Topic replies
v2ex nodes	/api/nodes/all.json	All nodes sorted by topic count

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🌐 New site adapter
• 📝 Documentation
• ♻️ Refactor
• 🔧 CI / build / tooling

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• I included output or screenshots when useful

Documentation (if adding/modifying an adapter)

• Added doc page under docs/adapters/ (if new adapter) — updated existing v2ex page
• Updated docs/adapters/index.md table (if new adapter)
• Updated sidebar in docs/.vitepress/config.mts (if new adapter) — N/A, v2ex entry already exists

Screenshots / Output

$ opencli v2ex node python --limit 5

  v2ex/node
┌──────┬──────────────────────────────────────────────┬──────────────┬─────────┐
│ Rank │ Title                                        │ Author       │ Replies │
├──────┼──────────────────────────────────────────────┼──────────────┼─────────┤
│ 1    │ 创造了 uv 的 Astral 公司被 OpenAI 收购       │ GPLer        │ 7       │
│ 2    │ 慎用 PyCharm Remote Development 功能          │ Deteriorator │ 13      │
│ 3    │ Python 3.15 JIT 的最新进展                    │ zxccv1876    │ 10      │
│ ...  │                                              │              │         │
└──────┴──────────────────────────────────────────────┴──────────────┴─────────┘

$ opencli v2ex replies 1000 --limit 3

  v2ex/replies
┌───────┬──────────┬─────────────────────────────────────────────┐
│ Floor │ Author   │ Content                                     │
├───────┼──────────┼─────────────────────────────────────────────┤
│ 1     │ romoo    │ 右下角的图标该变成三个了。 ^^               │
│ 2     │ Livid    │ 欢迎各位尝试重新上传头像以使用这个新架构 :) │
│ 3     │ airwolf  │ OK，我去换头像！                            │
└───────┴──────────┴─────────────────────────────────────────────┘

$ opencli v2ex member Livid

  v2ex/member
┌──────────┬───────────────────────────┬─────────────────┬────────┬─────────┬──────────┐
│ Username │ Tagline                   │ Website         │ Github │ Twitter │ Location │
├──────────┼───────────────────────────┼─────────────────┼────────┼─────────┼──────────┤
│ Livid    │ Remember the bigger green │ sepia.sol.build │        │         │          │
└──────────┴───────────────────────────┴─────────────────┴────────┴─────────┴──────────┘

$ opencli v2ex nodes --limit 5

  v2ex/nodes
┌──────┬────────────┬──────────┬────────┬───────┐
│ Rank │ Name       │ Title    │ Topics │ Stars │
├──────┼────────────┼──────────┼────────┼───────┤
│ 1    │ qna        │ 问与答   │ 237740 │ 4476  │
│ 2    │ all4all    │ 二手交易 │ 143686 │ 8245  │
│ 3    │ programmer │ 程序员   │ 70190  │ 9596  │
│ 4    │ jobs       │ 酷工作   │ 60143  │ 6474  │
│ 5    │ share      │ 分享发现 │ 45765  │ 6260  │
└──────┴────────────┴──────────┴────────┴───────┘

[Astro-Han]

Note: CI failures (build, unit-test shard 2, e2e-headed) are caused by a missing turndown dependency in src/clis/zhihu/download.test.ts and src/download/article-download.ts. This is a pre-existing issue on the main branch (same CI failures visible on the latest main commit). Not related to this PR's changes.