chore: remove bundled XiaoZhi source and link upstream board

README.md

@@ -81,7 +81,7 @@ Factory firmware (restores the out-of-box demo): download the file whose name co
 | [10_U8G2_Test](examples/arduino/examples/10_U8G2_Test/) | U8g2 |
 
 Libraries used by the sketches are bundled in [`examples/arduino/libraries`](examples/arduino/libraries/).
-ESPHome configurations are in [`examples/esphome`](examples/esphome/README.md) and the XiaoZhi AI firmware source in [`examples/xiaozhi`](examples/xiaozhi/).
+ESPHome configurations are in [`examples/esphome`](examples/esphome/README.md). The XiaoZhi AI firmware source for this board is in the upstream [xiaozhi-esp32](https://github.com/78/xiaozhi-esp32/tree/main/main/boards/waveshare/esp32-s3-rlcd-4.2) repository.
 
 ## 🛠️ Development Environment
 

README_ZH.md

@@ -79,7 +79,7 @@ ESP32-S3-RLCD-4.2 是一块 AIoT 开发板，采用 ESP32-S3-WROOM-1-N16R8 模
 | [10_U8G2_Test](examples/arduino/examples/10_U8G2_Test/README_ZH.md) | U8g2 |
 
 草图使用的库随仓库提供，位于 [`examples/arduino/libraries`](examples/arduino/libraries/)。
-ESPHome 配置位于 [`examples/esphome`](examples/esphome/README_ZH.md)，小智 AI 固件源码位于 [`examples/xiaozhi`](examples/xiaozhi/)。
+ESPHome 配置位于 [`examples/esphome`](examples/esphome/README_ZH.md)。本产品的小智 AI 固件源码在上游 [xiaozhi-esp32](https://github.com/78/xiaozhi-esp32/tree/main/main/boards/waveshare/esp32-s3-rlcd-4.2) 仓库。
 
 ## 🛠️ 开发环境