feat(skill): refactor skill system with router + references structure (#192)

Refactors SKILL.md into a router + reference documentation system:
- Main SKILL.md now contains routing table and quick commands
- Detailed docs split into references/ (search, social, career, dev, web, video)
- CLI skill install copies entire directory including references/
- Resolves conflicts with recent merges (#210, #213)
- Fixes xreach→bird in quick commands

Original PR by @Citrus086, merged with conflict resolution.

Co-Authored-By: Citrus086 <Citrus086@users.noreply.github.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

agent_reach/skill/references/video.md

@@ -0,0 +1,88 @@
+# 视频/播客
+
+YouTube、B站、小宇宙播客的字幕和转录。
+
+## YouTube (yt-dlp)
+
+### 获取视频元数据
+
+```bash
+yt-dlp --dump-json "URL"
+```
+
+### 下载字幕
+
+```bash
+# 下载字幕 (不下载视频)
+yt-dlp --write-sub --write-auto-sub --sub-lang "zh-Hans,zh,en" --skip-download -o "/tmp/%(id)s" "URL"
+
+# 然后读取 .vtt 文件
+cat /tmp/VIDEO_ID.*.vtt
+```
+
+### 搜索视频
+
+```bash
+yt-dlp --dump-json "ytsearch5:query"
+```
+
+## B站 / Bilibili (yt-dlp)
+
+### 获取视频元数据
+
+```bash
+yt-dlp --dump-json "https://www.bilibili.com/video/BVxxx"
+```
+
+### 下载字幕
+
+```bash
+yt-dlp --write-sub --write-auto-sub --sub-lang "zh-Hans,zh,en" --convert-subs vtt --skip-download -o "/tmp/%(id)s" "URL"
+```
+
+> **注意**: 服务器 IP 可能遇到 412 错误。使用 `--cookies-from-browser chrome` 或配置代理。
+
+## 小宇宙播客 / Xiaoyuzhou Podcast
+
+### 转录单集播客
+
+```bash
+# 输出 Markdown 文件到 /tmp/
+~/.agent-reach/tools/xiaoyuzhou/transcribe.sh "https://www.xiaoyuzhoufm.com/episode/EPISODE_ID"
+```
+
+### 前置要求
+
+1. **ffmpeg**: `brew install ffmpeg`
+2. **Groq API Key** (免费): https://console.groq.com/keys
+3. **配置 Key**: `agent-reach configure groq-key YOUR_KEY`
+4. **首次运行**: `agent-reach install --env=auto` 安装工具
+
+### 检查状态
+
+```bash
+agent-reach doctor
+```
+
+> 输出 Markdown 文件默认保存到 `/tmp/`。
+
+## 抖音视频解析
+
+```bash
+# 解析视频信息
+mcporter call 'douyin.parse_douyin_video_info(share_link: "https://v.douyin.com/xxx/")'
+
+# 获取无水印下载链接
+mcporter call 'douyin.get_douyin_download_link(share_link: "https://v.douyin.com/xxx/")'
+```
+
+> 详见 [social.md](social.md#抖音--douyin)
+
+## 选择指南
+
+| 场景 | 推荐工具 |
+|-----|---------|
+| YouTube 字幕 | yt-dlp |
+| B站字幕 | yt-dlp |
+| 播客转录 | 小宇宙 transcribe.sh |
+| 抖音视频解析 | douyin MCP |