🖼️ Refresh v3 screenshots and update READMEs

New demo screenshots (old set archived under images/old), README
feature list, AI-agent quick start, and upgrade section.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.zh-cn.md

@@ -1,7 +1,7 @@
 [English](https://github.com/nunocoracao/blowfish/blob/main/README.md) | [Français](https://github.com/nunocoracao/blowfish/blob/main/README.fr.md) | [Deutsch](https://github.com/nunocoracao/blowfish/blob/main/README.de.md) | [Português (PT)](https://github.com/nunocoracao/blowfish/blob/main/README.pt-pt.md) | [Português (BR)](https://github.com/nunocoracao/blowfish/blob/main/README.pt-br.md) | [Español](https://github.com/nunocoracao/blowfish/blob/main/README.es.md) | [日本語](https://github.com/nunocoracao/blowfish/blob/main/README.ja.md) | 简体中文 | [Indonesian](https://github.com/nunocoracao/blowfish/blob/main/README.id.md)
 # Blowfish
 [![Netlify Status](https://api.netlify.com/api/v1/badges/6e5256d4-3148-4d69-879c-310341020fe9/deploy-status)](https://app.netlify.com/sites/snazzy-dango-efb2ec/deploys)
-[![Minimum Hugo Version](https://img.shields.io/static/v1?label=min-HUGO-version&message=0.158.0&color=blue&logo=hugo)](https://github.com/gohugoio/hugo/releases/tag/v0.158.0)
+[![Minimum Hugo Version](https://img.shields.io/static/v1?label=min-HUGO-version&message=0.162.0&color=blue&logo=hugo)](https://github.com/gohugoio/hugo/releases/tag/v0.162.0)
 [![GitHub](https://img.shields.io/github/license/nunocoracao/blowfish)](https://github.com/nunocoracao/blowfish/blob/main/LICENSE)
 [![Blowfish](https://img.shields.io/badge/Hugo--Themes-@Blowfish-blue)](https://themes.gohugo.io/themes/blowfish/)
 ![code-size](https://img.shields.io/github/languages/code-size/nunocoracao/blowfish)
@@ -134,7 +134,7 @@ blowfish-tools new mynewsite
 
    ```toml
    [[imports]]
-   path = "github.com/nunocoracao/blowfish/v2"
+   path = "github.com/nunocoracao/blowfish/v3"
    ```
 
 3. 运行 `hugo server` 启动你的本地服务器，本主题就会自动下载。