docs: add devtools mcp guidance

docs/plan.md

@@ -59,7 +59,7 @@ docs/
 - [x] T011 [US1] Superadmin 页面自动化步骤
 
 ### Phase 3
-- [x] T020 [US2] 更新验证文档
+- [x] T020 [US2] 更新验证文档（含 DevTools MCP 指引）
 
 ## Dependencies
 

docs/seed_verification.md

@@ -8,6 +8,12 @@
 - Portal dev server proxies `/v1` to `http://localhost:8080` (`frontend/portal/vite.config.js`).
 - Superadmin dev server proxies `/super/v1` and `/v1` to `http://localhost:8080` (`frontend/superadmin/vite.config.mjs`).
 
+## Chrome DevTools MCP
+
+- Start Chrome with remote debugging: `google-chrome --remote-debugging-port=9222`.
+- Use MCP to connect at `http://127.0.0.1:9222`.
+- Open target URLs via MCP and run page-level assertions (no API-level calls required).
+
 ## Run Seed
 
 - Execute `go run ./backend/main.go seed`.