Migrate OpenWrite integration to TechGrow

[yunhe-dev]

Summary

• migrate article readmore integration from OpenWrite to TechGrow
• rename component from OpenWrite to TechGrow and update usage in post page route
• add TechGrow configuration fields in blog config
• fix readmore/captcha positioning and validation edge cases

Key Changes

• components/OpenWrite.js -> components/TechGrow.js
• pages/[prefix]/index.js: replace OpenWrite usage with TechGrow
• blog.config.js: add TechGrow related config keys
• multiple follow-up fixes for DOM placement and form validation

Notes

This PR keeps behavior-compatible readmore flow while switching the provider to TechGrow.

[vercel]

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[yunhe-dev]

已补充 TechGrow 配置说明（见 blog.config.js）。

在 Notion 的 Config 页面可直接用同名键配置（优先于 blog.config.js）：

必填：

• TECH_GROW_BLOG_ID
• TECH_GROW_NAME
• TECH_GROW_QRCODE
• TECH_GROW_KEYWORD

常用：

• TECH_GROW_ARTICLE_CONTENT_ID（默认 notion-article）
• TECH_GROW_BTN_TEXT
• TECH_GROW_VALIDITY_DURATION（小时）

名单规则：

• TECH_GROW_WHITE_LIST：这些路径放行
• TECH_GROW_YELLOW_LIST：仅这些路径启用拦截（优先级高于白名单）

[yunhe-dev]

创建Blog id: https://open.techgrow.cn/#/home ,官方博客地址：https://docs.techgrow.cn/v1/wechat/tutorial/hexo/#%E6%B3%A8%E5%86%8C%E5%8D%9A%E5%AE%A2

[yunhe-dev]

改用 TechGrow公众号引流之后的博客演示地址：https://yunhe.dev/