feat(GRO-2158): route planner page at /admin/routes (#60)

src/App.tsx

@@ -8,6 +8,7 @@ import { StaffPage } from "./pages/Staff.js";
 import { InvoicesPage } from "./pages/Invoices.js";
 import { BookPage } from "./pages/Book.js";
 import { ReportsPage } from "./pages/Reports.js";
+import { RoutesPage } from "./pages/Routes.js";
 import { GroupBookingPage } from "./pages/GroupBooking.js";
 import { SettingsPage } from "./pages/Settings.js";
 import { BookingConfirmedPage } from "./pages/BookingConfirmed.js";
@@ -175,6 +176,7 @@ const NAV_LINKS = [
   { to: "/admin/staff", label: "Staff" },
   { to: "/admin/invoices", label: "Invoices" },
   { to: "/admin/group-bookings", label: "Group Bookings" },
+  { to: "/admin/routes", label: "Routes" },
   { to: "/admin/reports", label: "Reports" },
   { to: "/admin/settings", label: "Settings" },
   { to: "/", label: "Customer Portal" },
@@ -303,6 +305,7 @@ function AdminLayout() {
           <Route path="/invoices" element={<InvoicesPage />} />
           <Route path="/book" element={<BookPage />} />
           <Route path="/group-bookings" element={<GroupBookingPage />} />
+          <Route path="/routes" element={<RoutesPage />} />
           <Route path="/reports" element={<ReportsPage />} />
           <Route path="/settings" element={<SettingsPage />} />
         </Routes>