docs: clarify QSL architecture role (#202)

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

Author: Pigbibi

README.md

@@ -1,5 +1,14 @@
 # FirstradePlatform
 
+
+## QSL architecture role
+
+- **Layer**: `runtime-platform`.
+- **Responsibility**: experimental Firstrade US equity execution runtime.
+- **Owns**: Firstrade-compatible runtime controls, generated orders, notifications.
+- **Consumes**: UsEquityStrategies, UsEquitySnapshotPipelines artifacts, QuantPlatformKit, QuantRuntimeSettings.
+- **Must not**: promote strategies without evidence or store secrets 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 @@
 # FirstradePlatform
 
+
+## QSL 架构角色
+
+- **层级**：`执行平台`。
+- **职责**：实验性 Firstrade 美股执行运行时。
+- **事实源/归属**：Firstrade-compatible runtime 控制、生成订单、通知。
+- **消费对象**：UsEquityStrategies、UsEquitySnapshotPipelines artifacts、QuantPlatformKit、QuantRuntimeSettings。
+- **禁止事项**：无证据推广策略或把 secrets 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。