feat: add sinafinance 7x24 news adapter (#131)

Based on PR #131 by larria, with fixes applied:
- Renamed command 724 → news for clarity
- Fixed indentation to 2-space project standard
- Added SinaNewsItem type (removed item: any)
- Added res.ok check + CliError for HTTP failures
- Added stripHtml() for rich_text content
- Updated README, README.zh-CN, SKILL.md

Co-authored-by: larria <1115524+larria@users.noreply.github.com>

README.zh-CN.md

@@ -146,6 +146,7 @@ npm install -g @jackwener/opencli@latest
 | **smzdm** | `search` | 浏览器 |
 | **weibo** | `hot` | 浏览器 |
 | **yahoo-finance** | `quote` | 浏览器 |
+| **sinafinance** | `news` | 🌐 公开 |
 
 ### 桌面应用适配器