Add an admin panel: orders dashboard, menu management, kitchen status

Introduces a role-gated /admin section (sidebar layout, requireAdmin
checked both in route loaders and independently in every admin server
function) with three sections:
- Orders: every order across all customers, and an admin-only order
  detail view nested under /admin so the sidebar persists and admin
  access bypasses the guest-token check.
- Menu: create/edit/delete menu items, their options, and their
  preparation steps; deleting an item with past orders is refused
  (protected by the orderItems FK) instead of crashing.
- Kitchen: read-only live view of every machine's busy/idle status and
  per-tag queue depth, with a manual refresh.

Also:
- Adds a `role` field to the user table (Better Auth additionalFields,
  input:false so it can't be self-assigned) and a db:seed-admin script
  to create/promote an admin account.
- Fixes a real bug found while building this: src/server/auth.ts's
  shared session helpers were plain exported functions using a
  server-only import, which the framework couldn't tree-shake out of
  the client bundle once shared across multiple server/*.ts modules —
  this silently broke hydration app-wide. Fixed with createServerOnlyFn.
- Removes the now-fully-unused @tanstack/devtools-vite plugin.
- Disables view transitions for in-admin navigation so the persistent
  sidebar doesn't cross-fade/shift on every click.
- Gives the "your orders" empty state the same visual treatment as the
  basket page's.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/routeTree.gen.ts

@@ -10,12 +10,20 @@
 
 import { Route as rootRouteImport } from './routes/__root'
 import { Route as IndexRouteImport } from './routes/index'
+import { Route as AdminRouteImport } from './routes/admin'
 import { Route as BasketRouteImport } from './routes/basket'
 import { Route as LoginRouteImport } from './routes/login'
 import { Route as SignupRouteImport } from './routes/signup'
+import { Route as AdminIndexRouteImport } from './routes/admin/index'
+import { Route as AdminKitchenRouteImport } from './routes/admin/kitchen'
 import { Route as ItemsMenuItemIdRouteImport } from './routes/items/$menuItemId'
 import { Route as OrdersIndexRouteImport } from './routes/orders/index'
 import { Route as OrdersOrderIdRouteImport } from './routes/orders/$orderId'
+import { Route as AdminMenuIndexRouteImport } from './routes/admin/menu/index'
+import { Route as AdminMenuMenuItemIdRouteImport } from './routes/admin/menu/$menuItemId'
+import { Route as AdminMenuNewRouteImport } from './routes/admin/menu/new'
+import { Route as AdminOrdersIndexRouteImport } from './routes/admin/orders/index'
+import { Route as AdminOrdersOrderIdRouteImport } from './routes/admin/orders/$orderId'
 import { Route as ApiAuthSplatRouteImport } from './routes/api/auth/$'
 
 const IndexRoute = IndexRouteImport.update({
@@ -23,6 +31,11 @@ const IndexRoute = IndexRouteImport.update({
   path: '/',
   getParentRoute: () => rootRouteImport,
 } as any)
+const AdminRoute = AdminRouteImport.update({
+  id: '/admin',
+  path: '/admin',
+  getParentRoute: () => rootRouteImport,
+} as any)
 const BasketRoute = BasketRouteImport.update({
   id: '/basket',
   path: '/basket',
@@ -38,6 +51,16 @@ const SignupRoute = SignupRouteImport.update({
   path: '/signup',
   getParentRoute: () => rootRouteImport,
 } as any)
+const AdminIndexRoute = AdminIndexRouteImport.update({
+  id: '/',
+  path: '/',
+  getParentRoute: () => AdminRoute,
+} as any)
+const AdminKitchenRoute = AdminKitchenRouteImport.update({
+  id: '/kitchen',
+  path: '/kitchen',
+  getParentRoute: () => AdminRoute,
+} as any)
 const ItemsMenuItemIdRoute = ItemsMenuItemIdRouteImport.update({
   id: '/items/$menuItemId',
   path: '/items/$menuItemId',
@@ -53,6 +76,31 @@ const OrdersOrderIdRoute = OrdersOrderIdRouteImport.update({
   path: '/orders/$orderId',
   getParentRoute: () => rootRouteImport,
 } as any)
+const AdminMenuIndexRoute = AdminMenuIndexRouteImport.update({
+  id: '/menu/',
+  path: '/menu/',
+  getParentRoute: () => AdminRoute,
+} as any)
+const AdminMenuMenuItemIdRoute = AdminMenuMenuItemIdRouteImport.update({
+  id: '/menu/$menuItemId',
+  path: '/menu/$menuItemId',
+  getParentRoute: () => AdminRoute,
+} as any)
+const AdminMenuNewRoute = AdminMenuNewRouteImport.update({
+  id: '/menu/new',
+  path: '/menu/new',
+  getParentRoute: () => AdminRoute,
+} as any)
+const AdminOrdersIndexRoute = AdminOrdersIndexRouteImport.update({
+  id: '/orders/',
+  path: '/orders/',
+  getParentRoute: () => AdminRoute,
+} as any)
+const AdminOrdersOrderIdRoute = AdminOrdersOrderIdRouteImport.update({
+  id: '/orders/$orderId',
+  path: '/orders/$orderId',
+  getParentRoute: () => AdminRoute,
+} as any)
 const ApiAuthSplatRoute = ApiAuthSplatRouteImport.update({
   id: '/api/auth/$',
   path: '/api/auth/$',
@@ -61,70 +109,117 @@ const ApiAuthSplatRoute = ApiAuthSplatRouteImport.update({
 
 export interface FileRoutesByFullPath {
   '/': typeof IndexRoute
+  '/admin': typeof AdminRouteWithChildren
   '/basket': typeof BasketRoute
   '/login': typeof LoginRoute
   '/signup': typeof SignupRoute
+  '/admin/kitchen': typeof AdminKitchenRoute
   '/items/$menuItemId': typeof ItemsMenuItemIdRoute
   '/orders/$orderId': typeof OrdersOrderIdRoute
+  '/admin/': typeof AdminIndexRoute
   '/orders/': typeof OrdersIndexRoute
+  '/admin/menu/$menuItemId': typeof AdminMenuMenuItemIdRoute
+  '/admin/menu/new': typeof AdminMenuNewRoute
+  '/admin/orders/$orderId': typeof AdminOrdersOrderIdRoute
   '/api/auth/$': typeof ApiAuthSplatRoute
+  '/admin/menu/': typeof AdminMenuIndexRoute
+  '/admin/orders/': typeof AdminOrdersIndexRoute
 }
 export interface FileRoutesByTo {
   '/': typeof IndexRoute
   '/basket': typeof BasketRoute
   '/login': typeof LoginRoute
   '/signup': typeof SignupRoute
+  '/admin/kitchen': typeof AdminKitchenRoute
   '/items/$menuItemId': typeof ItemsMenuItemIdRoute
   '/orders/$orderId': typeof OrdersOrderIdRoute
+  '/admin': typeof AdminIndexRoute
   '/orders': typeof OrdersIndexRoute
+  '/admin/menu/$menuItemId': typeof AdminMenuMenuItemIdRoute
+  '/admin/menu/new': typeof AdminMenuNewRoute
+  '/admin/orders/$orderId': typeof AdminOrdersOrderIdRoute
   '/api/auth/$': typeof ApiAuthSplatRoute
+  '/admin/menu': typeof AdminMenuIndexRoute
+  '/admin/orders': typeof AdminOrdersIndexRoute
 }
 export interface FileRoutesById {
   __root__: typeof rootRouteImport
   '/': typeof IndexRoute
+  '/admin': typeof AdminRouteWithChildren
   '/basket': typeof BasketRoute
   '/login': typeof LoginRoute
   '/signup': typeof SignupRoute
+  '/admin/kitchen': typeof AdminKitchenRoute
   '/items/$menuItemId': typeof ItemsMenuItemIdRoute
   '/orders/$orderId': typeof OrdersOrderIdRoute
+  '/admin/': typeof AdminIndexRoute
   '/orders/': typeof OrdersIndexRoute
+  '/admin/menu/$menuItemId': typeof AdminMenuMenuItemIdRoute
+  '/admin/menu/new': typeof AdminMenuNewRoute
+  '/admin/orders/$orderId': typeof AdminOrdersOrderIdRoute
   '/api/auth/$': typeof ApiAuthSplatRoute
+  '/admin/menu/': typeof AdminMenuIndexRoute
+  '/admin/orders/': typeof AdminOrdersIndexRoute
 }
 export interface FileRouteTypes {
   fileRoutesByFullPath: FileRoutesByFullPath
   fullPaths:
     | '/'
+    | '/admin'
     | '/basket'
     | '/login'
     | '/signup'
+    | '/admin/kitchen'
     | '/items/$menuItemId'
     | '/orders/$orderId'
+    | '/admin/'
     | '/orders/'
+    | '/admin/menu/$menuItemId'
+    | '/admin/menu/new'
+    | '/admin/orders/$orderId'
     | '/api/auth/$'
+    | '/admin/menu/'
+    | '/admin/orders/'
   fileRoutesByTo: FileRoutesByTo
   to:
     | '/'
     | '/basket'
     | '/login'
     | '/signup'
+    | '/admin/kitchen'
     | '/items/$menuItemId'
     | '/orders/$orderId'
+    | '/admin'
     | '/orders'
+    | '/admin/menu/$menuItemId'
+    | '/admin/menu/new'
+    | '/admin/orders/$orderId'
     | '/api/auth/$'
+    | '/admin/menu'
+    | '/admin/orders'
   id:
     | '__root__'
     | '/'
+    | '/admin'
     | '/basket'
     | '/login'
     | '/signup'
+    | '/admin/kitchen'
     | '/items/$menuItemId'
     | '/orders/$orderId'
+    | '/admin/'
     | '/orders/'
+    | '/admin/menu/$menuItemId'
+    | '/admin/menu/new'
+    | '/admin/orders/$orderId'
     | '/api/auth/$'
+    | '/admin/menu/'
+    | '/admin/orders/'
   fileRoutesById: FileRoutesById
 }
 export interface RootRouteChildren {
   IndexRoute: typeof IndexRoute
+  AdminRoute: typeof AdminRouteWithChildren
   BasketRoute: typeof BasketRoute
   LoginRoute: typeof LoginRoute
   SignupRoute: typeof SignupRoute
@@ -143,6 +238,13 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof IndexRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/admin': {
+      id: '/admin'
+      path: '/admin'
+      fullPath: '/admin'
+      preLoaderRoute: typeof AdminRouteImport
+      parentRoute: typeof rootRouteImport
+    }
     '/basket': {
       id: '/basket'
       path: '/basket'
@@ -164,6 +266,20 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof SignupRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/admin/': {
+      id: '/admin/'
+      path: '/'
+      fullPath: '/admin/'
+      preLoaderRoute: typeof AdminIndexRouteImport
+      parentRoute: typeof AdminRoute
+    }
+    '/admin/kitchen': {
+      id: '/admin/kitchen'
+      path: '/kitchen'
+      fullPath: '/admin/kitchen'
+      preLoaderRoute: typeof AdminKitchenRouteImport
+      parentRoute: typeof AdminRoute
+    }
     '/items/$menuItemId': {
       id: '/items/$menuItemId'
       path: '/items/$menuItemId'
@@ -185,6 +301,41 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof OrdersOrderIdRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/admin/menu/': {
+      id: '/admin/menu/'
+      path: '/menu'
+      fullPath: '/admin/menu/'
+      preLoaderRoute: typeof AdminMenuIndexRouteImport
+      parentRoute: typeof AdminRoute
+    }
+    '/admin/menu/$menuItemId': {
+      id: '/admin/menu/$menuItemId'
+      path: '/menu/$menuItemId'
+      fullPath: '/admin/menu/$menuItemId'
+      preLoaderRoute: typeof AdminMenuMenuItemIdRouteImport
+      parentRoute: typeof AdminRoute
+    }
+    '/admin/menu/new': {
+      id: '/admin/menu/new'
+      path: '/menu/new'
+      fullPath: '/admin/menu/new'
+      preLoaderRoute: typeof AdminMenuNewRouteImport
+      parentRoute: typeof AdminRoute
+    }
+    '/admin/orders/': {
+      id: '/admin/orders/'
+      path: '/orders'
+      fullPath: '/admin/orders/'
+      preLoaderRoute: typeof AdminOrdersIndexRouteImport
+      parentRoute: typeof AdminRoute
+    }
+    '/admin/orders/$orderId': {
+      id: '/admin/orders/$orderId'
+      path: '/orders/$orderId'
+      fullPath: '/admin/orders/$orderId'
+      preLoaderRoute: typeof AdminOrdersOrderIdRouteImport
+      parentRoute: typeof AdminRoute
+    }
     '/api/auth/$': {
       id: '/api/auth/$'
       path: '/api/auth/$'
@@ -195,8 +346,31 @@ declare module '@tanstack/react-router' {
   }
 }
 
+interface AdminRouteChildren {
+  AdminKitchenRoute: typeof AdminKitchenRoute
+  AdminIndexRoute: typeof AdminIndexRoute
+  AdminMenuMenuItemIdRoute: typeof AdminMenuMenuItemIdRoute
+  AdminMenuNewRoute: typeof AdminMenuNewRoute
+  AdminOrdersOrderIdRoute: typeof AdminOrdersOrderIdRoute
+  AdminMenuIndexRoute: typeof AdminMenuIndexRoute
+  AdminOrdersIndexRoute: typeof AdminOrdersIndexRoute
+}
+
+const AdminRouteChildren: AdminRouteChildren = {
+  AdminKitchenRoute: AdminKitchenRoute,
+  AdminIndexRoute: AdminIndexRoute,
+  AdminMenuMenuItemIdRoute: AdminMenuMenuItemIdRoute,
+  AdminMenuNewRoute: AdminMenuNewRoute,
+  AdminOrdersOrderIdRoute: AdminOrdersOrderIdRoute,
+  AdminMenuIndexRoute: AdminMenuIndexRoute,
+  AdminOrdersIndexRoute: AdminOrdersIndexRoute,
+}
+
+const AdminRouteWithChildren = AdminRoute._addFileChildren(AdminRouteChildren)
+
 const rootRouteChildren: RootRouteChildren = {
   IndexRoute: IndexRoute,
+  AdminRoute: AdminRouteWithChildren,
   BasketRoute: BasketRoute,
   LoginRoute: LoginRoute,
   SignupRoute: SignupRoute,