docs: clarify QSL architecture role (#301)

Co-authored-by: Codex <noreply@openai.com>

Author: Pigbibi

README.md

@@ -1,5 +1,14 @@
 # LongBridgePlatform
 
+
+## QSL architecture role
+
+- **Layer**: `runtime-platform`.
+- **Responsibility**: LongBridge US/HK execution runtime.
+- **Owns**: LongBridge connectivity, regional runtime settings, dry-run/live controls.
+- **Consumes**: UsEquityStrategies, HkEquityStrategies, snapshot artifacts, QuantPlatformKit, QuantRuntimeSettings.
+- **Must not**: own strategy research logic or store credentials in Git.
+
 [Chinese README](README.zh-CN.md)
 
 > Investing involves risk. This project does not provide investment advice and is for education, research, and engineering review only.

README.zh-CN.md

@@ -1,5 +1,14 @@
 # LongBridgePlatform
 
+
+## QSL 架构角色
+
+- **层级**：`执行平台`。
+- **职责**：LongBridge 美股/港股执行运行时。
+- **事实源/归属**：LongBridge 连接、区域 runtime 设置、dry-run/live 控制。
+- **消费对象**：UsEquityStrategies、HkEquityStrategies、snapshot artifacts、QuantPlatformKit、QuantRuntimeSettings。
+- **禁止事项**：承载策略研究逻辑或把凭据写入 Git。
+
 [English README](README.md)
 
 > 投资有风险。本项目不构成投资建议，仅用于学习、研究和工程审阅。