Rename admin routes to ISAC

docs/DESIGN_SYSTEM.md

@@ -435,7 +435,7 @@ Do not communicate state by color alone; include a label, icon, or pattern.
 
 ## Adding a new admin module
 
-1. Add the route beneath `src/routes/admin`.
+1. Add the route beneath `src/routes/isac`.
 2. Register it in the admin layout navigation.
 3. Start with the module toolbar and KPI row.
 4. Reuse dashboard editor and table classes.