chore: add demo profile and local api proxy

docs/deploy/local-runbook.md

@@ -37,6 +37,19 @@ Backend API: http://localhost:8080
 Knife4j docs: http://localhost:8080/doc.html
 ```
 
+If Docker/MySQL are not available or port `8080` is already occupied, use the no-database demo profile:
+
+```powershell
+cd backend
+mvn spring-boot:run "-Dspring-boot.run.profiles=demo"
+```
+
+Demo profile URL:
+
+```text
+Backend API: http://localhost:18080
+```
+
 Demo accounts:
 
 ```text
@@ -60,6 +73,13 @@ URL:
 http://localhost:5173
 ```
 
+During local development, `/api` is proxied to `http://localhost:8080` by default. If the backend uses another port:
+
+```powershell
+$env:VITE_API_PROXY_TARGET="http://localhost:18080"
+npm run dev
+```
+
 ## Start Rider H5
 
 ```powershell
@@ -74,6 +94,8 @@ URL:
 http://localhost:5174
 ```
 
+Rider H5 uses the same `/api` dev proxy behavior as the admin web.
+
 ## Open Miniapp
 
 Use WeChat DevTools to open: