refactor: remove Douyin, Weibo and WeChat channels (#347)

All three had rotted past honest usability:
- Douyin's upstream (yzfly/douyin-mcp-server) is archived and required a
  4-step manual local-server setup nobody could complete
- Weibo depended on an unmaintained personal fork (mcp-server-weibo)
- WeChat full-article reading was increasingly blocked by anti-bot
  (#339) while doctor still advertised it as zero-config

Removes the channel files, installers, skill routing/trigger entries,
reference sections and README rows (zh+en). Honest counts: 13 platforms,
6 zero-config. They can return when maintained upstreams exist.

Follows the v1.4.0 precedent of removing Discord/Toutiao (#234).

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

agent_reach/skill/references/web.md

@@ -1,6 +1,6 @@
 # 网页阅读
 
-通用网页、微信公众号、RSS。
+通用网页、RSS。
 
 ## 通用网页 (Jina Reader)
 
@@ -29,30 +29,6 @@ mcporter call 'web-reader.webReader(url: "https://example.com", return_format: "
 
 **适用场景**: 需要更精确控制输出格式时使用。
 
-## 微信公众号 / WeChat Articles
-
-### 搜索公众号文章（通过 Exa）
-
-```bash
-# 搜索微信公众号文章
-mcporter call 'exa.web_search_exa(query: "搜索关键词", numResults: 5, includeDomains: ["mp.weixin.qq.com"])'
-```
-
-### 阅读公众号文章全文（通过 Exa）
-
-```bash
-# 抓取文章全文
-mcporter call 'exa.crawling_exa(urls: ["https://mp.weixin.qq.com/s/ARTICLE_ID"], maxCharacters: 10000)'
-```
-
-### 可选：Camoufox 阅读（反爬更强）
-
-```bash
-cd ~/.agent-reach/tools/wechat-article-for-ai && python3 main.py "https://mp.weixin.qq.com/s/ARTICLE_ID"
-```
-
-> **注意**: Jina Reader 无法读取微信文章（被 CAPTCHA 拦截），推荐用 Exa。
-
 ## RSS (feedparser)
 
 ```python
@@ -71,6 +47,4 @@ for e in feedparser.parse('FEED_URL').entries[:5]:
 |-----|---------|
 | 通用网页 | Jina Reader (`curl r.jina.ai`) |
 | 需要图片/格式控制 | web-reader MCP |
-| 微信公众号 | Exa (搜索+阅读) / Camoufox (可选阅读) |
 | RSS 订阅 | feedparser |
-| 微博/知乎等 | Jina Reader |