feat: update readme and i18n

README.en.md

@@ -65,6 +65,14 @@
     - Add suffix `-low` to set low reasoning effort
 17. 🔄 Thinking to content option `thinking_to_content` in `Channel->Edit->Channel Extra Settings`, default is `false`, when `true`, the `reasoning_content` of the thinking content will be converted to `<think>` tags and concatenated to the content returned.
 18. 🔄 Model rate limit, support setting total request limit and successful request limit in `System Settings->Rate Limit Settings`
+19. 💰 Cache billing support, when enabled can charge a configurable ratio for cache hits:
+    1. Set `Prompt Cache Ratio` in `System Settings -> Operation Settings`
+    2. Set `Prompt Cache Ratio` in channel settings, range 0-1 (e.g., 0.5 means 50% charge on cache hits)
+    3. Supported channels:
+        - [x] OpenAI
+        - [x] Azure 
+        - [x] DeepSeek
+        - [ ] Claude
 
 ## Model Support
 This version additionally supports: