docs: 添加 Simple Mode 说明和 Antigravity 已知问题

README.md

@@ -297,6 +297,16 @@ go generate ./cmd/server
 
 ---
 
+## Simple Mode
+
+Simple Mode is designed for individual developers or internal teams who want quick access without full SaaS features.
+
+- Enable: Set environment variable `RUN_MODE=simple`
+- Difference: Hides SaaS-related features and skips billing process
+- Security note: In production, you must also set `SIMPLE_MODE_CONFIRM=true` to allow startup
+
+---
+
 ## Antigravity Support
 
 Sub2API supports [Antigravity](https://antigravity.so/) accounts. After authorization, dedicated endpoints are available for Claude and Gemini models.
@@ -321,6 +331,12 @@ Antigravity accounts support optional **hybrid scheduling**. When enabled, the g
 
 > **⚠️ Warning**: Anthropic Claude and Antigravity Claude **cannot be mixed within the same conversation context**. Use groups to isolate them properly.
 
+### Known Issues
+
+In Claude Code, Plan Mode cannot exit automatically. (Normally when using the native Claude API, after planning is complete, Claude Code will pop up options for users to approve or reject the plan.)
+
+**Workaround**: Press `Shift + Tab` to manually exit Plan Mode, then type your response to approve or reject the plan.
+
 ---
 
 ## Project Structure

README_CN.md

@@ -331,6 +331,10 @@ Antigravity 账户支持可选的**混合调度**功能。开启后，通用端
 
 > **⚠️ 注意**：Anthropic Claude 和 Antigravity Claude **不能在同一上下文中混合使用**，请通过分组功能做好隔离。
 
+
+### 已知问题
+在 Claude Code 中，无法自动退出Plan Mode。（正常使用原生Claude Api时，Plan 完成后，Claude Code会弹出弹出选项让用户同意或拒绝Plan。） 
+解决办法：shift + Tab，手动退出Plan mode，然后输入内容 告诉 Claude Code 同意或拒绝 Plan
 ---
 
 ## 项目结构