feat: Complete licensing module with admin and customer UIs

Admin SPA:
- Licenses list page with search, filter, pagination
- License detail page with activation history
- Copy license key, view details, revoke functionality

Customer SPA:
- My Account > Licenses page
- View licenses with activation info
- Copy license key
- Deactivate devices

Backend integration:
- Routes registered in App.tsx and Account/index.tsx
- License nav item in account sidebar (conditional on module enabled)

admin-spa/src/App.tsx

@@ -19,6 +19,8 @@ import ProductEdit from '@/routes/Products/Edit';
 import ProductCategories from '@/routes/Products/Categories';
 import ProductTags from '@/routes/Products/Tags';
 import ProductAttributes from '@/routes/Products/Attributes';
+import Licenses from '@/routes/Products/Licenses';
+import LicenseDetail from '@/routes/Products/Licenses/Detail';
 import CouponsIndex from '@/routes/Marketing/Coupons';
 import CouponNew from '@/routes/Marketing/Coupons/New';
 import CouponEdit from '@/routes/Marketing/Coupons/Edit';
@@ -541,6 +543,8 @@ function AppRoutes() {
       <Route path="/products/categories" element={<ProductCategories />} />
       <Route path="/products/tags" element={<ProductTags />} />
       <Route path="/products/attributes" element={<ProductAttributes />} />
+      <Route path="/products/licenses" element={<Licenses />} />
+      <Route path="/products/licenses/:id" element={<LicenseDetail />} />
 
       {/* Orders */}
       <Route path="/orders" element={<OrdersIndex />} />