docs(licheervnano): sync RV Claw section and board images across all languages

[SiYue-ZO]

Summary

• Add LicheeRV Nano board image and Sipeed official docs link to English and pt-BR licheervnano pages
• Add RV Claw section (intro, custom image download, flashing instructions, Sipeed docs link) to English and pt-BR translations
• All three languages (zh-Hans, en, pt-BR) are now in sync for the licheervnano installation page

[916BGAI]

It is suggested to convert these indented paragraphs into normal list items.

- Flashing: You can use balenaEtcher to flash the image directly to an SD card; or decompress the `.xz` file first and use the `dd` command to flash it.

- The expansion board function code in the image is based on Python, located at `/opt/app_picoclaw` ([source code](https://github.com/sipeed/rvclaw)), making it easy to customize and develop further as needed.

In the Chinese text, it is recommended to add a space after "RV Claw" to keep formatting consistent.

-RV Claw定制镜像下载：
+RV Claw 定制镜像下载：

-RV Claw的更多详细信息，请参考 [Sipeed 官方文档](https://wiki.sipeed.com/hardware/zh/lichee/RV_Nano/7_picoclaw_board.html)。
+RV Claw 的更多详细信息，请参考 [Sipeed 官方文档](https://wiki.sipeed.com/hardware/zh/lichee/RV_Nano/7_picoclaw_board.html)。

[SiYue-ZO]

It is suggested to convert these indented paragraphs into normal list items.

- Flashing: You can use balenaEtcher to flash the image directly to an SD card; or decompress the `.xz` file first and use the `dd` command to flash it.

- The expansion board function code in the image is based on Python, located at `/opt/app_picoclaw` ([source code](https://github.com/sipeed/rvclaw)), making it easy to customize and develop further as needed.

In the Chinese text, it is recommended to add a space after "RV Claw" to keep formatting consistent.

-RV Claw定制镜像下载：
+RV Claw 定制镜像下载：

-RV Claw的更多详细信息，请参考 [Sipeed 官方文档](https://wiki.sipeed.com/hardware/zh/lichee/RV_Nano/7_picoclaw_board.html)。
+RV Claw 的更多详细信息，请参考 [Sipeed 官方文档](https://wiki.sipeed.com/hardware/zh/lichee/RV_Nano/7_picoclaw_board.html)。

It is suggested to convert these indented paragraphs into normal list items.

- Flashing: You can use balenaEtcher to flash the image directly to an SD card; or decompress the `.xz` file first and use the `dd` command to flash it.

- The expansion board function code in the image is based on Python, located at `/opt/app_picoclaw` ([source code](https://github.com/sipeed/rvclaw)), making it easy to customize and develop further as needed.

In the Chinese text, it is recommended to add a space after "RV Claw" to keep formatting consistent.

-RV Claw定制镜像下载：
+RV Claw 定制镜像下载：

-RV Claw的更多详细信息，请参考 [Sipeed 官方文档](https://wiki.sipeed.com/hardware/zh/lichee/RV_Nano/7_picoclaw_board.html)。
+RV Claw 的更多详细信息，请参考 [Sipeed 官方文档](https://wiki.sipeed.com/hardware/zh/lichee/RV_Nano/7_picoclaw_board.html)。

Modified