chore(readme): update screenshots for different languages

- Replace `mobile_dark.webp`, `mobile_light.webp`, `desktop_dark.webp`, and `desktop_light.webp` with language-specific screenshots in the `res/screenshot/` directory.
- Update the references to these screenshots in `README.md` and `README.zh.md` to include language indicators.

README.md

@@ -45,17 +45,17 @@
 ### Mobile
 
 <picture>
-  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/mobile_dark.webp">
-  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/mobile_light.webp">
-  <img alt="The mobile screenshot for moodiary." src="res/screenshot/mobile_light.webp">
+  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/mobile_dark_en.webp">
+  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/mobile_light_en.webp">
+  <img alt="The mobile screenshot for moodiary." src="res/screenshot/mobile_light_en.webp">
 </picture>
 
 ### Desktop
 
 <picture>
-  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/desktop_dark.webp">
-  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/desktop_light.webp">
-  <img alt="The desktop screenshot for moodiary." src="res/screenshot/desktop_light.webp">
+  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/desktop_dark_en.webp">
+  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/desktop_light_en.webp">
+  <img alt="The desktop screenshot for moodiary." src="res/screenshot/desktop_light_en.webp">
 </picture>
 
 ## 🚀 Installation guide

README.zh.md

@@ -45,17 +45,17 @@
 ### 移动端
 
 <picture>
-  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/mobile_dark.webp">
-  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/mobile_light.webp">
-  <img alt="The mobile screenshot for moodiary." src="res/screenshot/mobile_light.webp">
+  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/mobile_dark_zh.webp">
+  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/mobile_light_zh.webp">
+  <img alt="The mobile screenshot for moodiary." src="res/screenshot/mobile_light_zh.webp">
 </picture>
 
 ### 桌面端
 
 <picture>
-  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/desktop_dark.webp">
-  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/desktop_light.webp">
-  <img alt="The desktop screenshot for moodiary." src="res/screenshot/desktop_light.webp">
+  <source media="(prefers-color-scheme: dark)" srcset="res/screenshot/desktop_dark_zh.webp">
+  <source media="(prefers-color-scheme: light)" srcset="res/screenshot/desktop_light_zh.webp">
+  <img alt="The desktop screenshot for moodiary." src="res/screenshot/desktop_light_zh.webp">
 </picture>
 
 ## 🚀 安装指南