feat: 新增小宇宙播客转文字渠道 (#124)

* feat: add Xiaoyuzhou podcast transcription channel

- New channel: 小宇宙播客 (xiaoyuzhoufm.com) → full text transcript
- Uses Groq Whisper API (free, no credit card needed)
- Auto-downloads audio, converts to low-bitrate MP3, splits by 25MB limit
- Supports any length podcast with automatic chunking
- Script installed to ~/.agent-reach/tools/xiaoyuzhou/transcribe.sh
- User just needs: agent-reach configure groq-key gsk_xxxxx
- Updated README (CN/EN), install.md, pyproject.toml

* docs: clarify Xiaoyuzhou setup — free key, limitations, step-by-step

---------

Co-authored-by: Panniantong <panniantong@users.noreply.github.com>

docs/README_en.md

@@ -69,6 +69,7 @@ Update Agent Reach: https://raw.githubusercontent.com/Panniantong/agent-reach/ma
 | 🏢 **Boss直聘** | Jina Reader (job pages) | Job search, greet recruiters | Tell your Agent "help me set up Boss直聘" |
 | 💬 **WeChat Articles** | Search + Read | Zero config | Search + read WeChat Official Account articles (full Markdown) ([wechat-article-for-ai](https://github.com/bzd6661/wechat-article-for-ai) + [miku_ai](https://github.com/GobinFan/Miku_Spider)) |
 | 📰 **Weibo** | Trending · Search · Feeds · Comments | Zero config | Hot search, content/user/topic search, feeds, comments ([mcp-server-weibo](https://github.com/Panniantong/mcp-server-weibo)) |
+| 🎙️ **Xiaoyuzhou Podcast** | Transcription | Free API key | Podcast audio → full text transcript via Groq Whisper (free) |
 | 🔍 **Web Search** | Search | Auto-configured | Auto-configured during install, free, no API key ([Exa](https://exa.ai) via [mcporter](https://github.com/nicepkg/mcporter)) |
 | 📦 **GitHub** | Read · Search | Zero config | [gh CLI](https://cli.github.com) powered. Public repos work immediately. `gh auth login` unlocks Fork, Issue, PR |
 | 📺 **YouTube** | Read · **Search** | Zero config | Subtitles + search across 1800+ video sites ([yt-dlp](https://github.com/yt-dlp/yt-dlp) ⭐148K) |
@@ -226,6 +227,7 @@ Each channel file only checks whether its upstream tool is installed and working
 | Boss直聘 | [mcp-bosszp](https://github.com/mucsbr/mcp-bosszp) | MCP server, job search + recruiter greeting |
 | WeChat Articles | [wechat-article-for-ai](https://github.com/bzd6661/wechat-article-for-ai) + [miku_ai](https://github.com/GobinFan/Miku_Spider) | Stealth browser for full article reading + Sogou search |
 | Weibo | `mcporter` | `mcporter call 'weibo.get_trendings(limit: 10)'` |
+| Xiaoyuzhou Podcast | `transcribe.sh` | `bash ~/.agent-reach/tools/xiaoyuzhou/transcribe.sh <URL>` |
 
 > 📌 These are the *current* choices. Don't like one? Swap out the file. That's the whole point of scaffolding.