Fix blank /students/new and /students/$id (missing Outlet)

students.tsx was the list AND the parent of students.new / students.$id but
rendered no <Outlet/>, so child routes never showed. Make students.tsx an
Outlet layout and move the list to students.index.tsx. Add an errorComponent
to students.new as a safety net.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/routeTree.gen.ts

@@ -20,6 +20,7 @@ import { Route as AuthenticatedDashboardRouteImport } from './routes/_authentica
 import { Route as AuthenticatedCalendarRouteImport } from './routes/_authenticated/calendar'
 import { Route as AuthenticatedAttendanceRouteImport } from './routes/_authenticated/attendance'
 import { Route as AuthenticatedAdminRouteImport } from './routes/_authenticated/admin'
+import { Route as AuthenticatedStudentsIndexRouteImport } from './routes/_authenticated/students.index'
 import { Route as AuthenticatedStudentsNewRouteImport } from './routes/_authenticated/students.new'
 import { Route as AuthenticatedStudentsIdRouteImport } from './routes/_authenticated/students.$id'
 
@@ -77,6 +78,12 @@ const AuthenticatedAdminRoute = AuthenticatedAdminRouteImport.update({
   path: '/admin',
   getParentRoute: () => AuthenticatedRouteRoute,
 } as any)
+const AuthenticatedStudentsIndexRoute =
+  AuthenticatedStudentsIndexRouteImport.update({
+    id: '/',
+    path: '/',
+    getParentRoute: () => AuthenticatedStudentsRoute,
+  } as any)
 const AuthenticatedStudentsNewRoute =
   AuthenticatedStudentsNewRouteImport.update({
     id: '/new',
@@ -102,6 +109,7 @@ export interface FileRoutesByFullPath {
   '/students': typeof AuthenticatedStudentsRouteWithChildren
   '/students/$id': typeof AuthenticatedStudentsIdRoute
   '/students/new': typeof AuthenticatedStudentsNewRoute
+  '/students/': typeof AuthenticatedStudentsIndexRoute
 }
 export interface FileRoutesByTo {
   '/': typeof IndexRoute
@@ -113,9 +121,9 @@ export interface FileRoutesByTo {
   '/forms': typeof AuthenticatedFormsRoute
   '/ledger': typeof AuthenticatedLedgerRoute
   '/messages': typeof AuthenticatedMessagesRoute
-  '/students': typeof AuthenticatedStudentsRouteWithChildren
   '/students/$id': typeof AuthenticatedStudentsIdRoute
   '/students/new': typeof AuthenticatedStudentsNewRoute
+  '/students': typeof AuthenticatedStudentsIndexRoute
 }
 export interface FileRoutesById {
   __root__: typeof rootRouteImport
@@ -132,6 +140,7 @@ export interface FileRoutesById {
   '/_authenticated/students': typeof AuthenticatedStudentsRouteWithChildren
   '/_authenticated/students/$id': typeof AuthenticatedStudentsIdRoute
   '/_authenticated/students/new': typeof AuthenticatedStudentsNewRoute
+  '/_authenticated/students/': typeof AuthenticatedStudentsIndexRoute
 }
 export interface FileRouteTypes {
   fileRoutesByFullPath: FileRoutesByFullPath
@@ -148,6 +157,7 @@ export interface FileRouteTypes {
     | '/students'
     | '/students/$id'
     | '/students/new'
+    | '/students/'
   fileRoutesByTo: FileRoutesByTo
   to:
     | '/'
@@ -159,9 +169,9 @@ export interface FileRouteTypes {
     | '/forms'
     | '/ledger'
     | '/messages'
-    | '/students'
     | '/students/$id'
     | '/students/new'
+    | '/students'
   id:
     | '__root__'
     | '/'
@@ -177,6 +187,7 @@ export interface FileRouteTypes {
     | '/_authenticated/students'
     | '/_authenticated/students/$id'
     | '/_authenticated/students/new'
+    | '/_authenticated/students/'
   fileRoutesById: FileRoutesById
 }
 export interface RootRouteChildren {
@@ -264,6 +275,13 @@ declare module '@tanstack/react-router' {
       preLoaderRoute: typeof AuthenticatedAdminRouteImport
       parentRoute: typeof AuthenticatedRouteRoute
     }
+    '/_authenticated/students/': {
+      id: '/_authenticated/students/'
+      path: '/'
+      fullPath: '/students/'
+      preLoaderRoute: typeof AuthenticatedStudentsIndexRouteImport
+      parentRoute: typeof AuthenticatedStudentsRoute
+    }
     '/_authenticated/students/new': {
       id: '/_authenticated/students/new'
       path: '/new'
@@ -284,11 +302,13 @@ declare module '@tanstack/react-router' {
 interface AuthenticatedStudentsRouteChildren {
   AuthenticatedStudentsIdRoute: typeof AuthenticatedStudentsIdRoute
   AuthenticatedStudentsNewRoute: typeof AuthenticatedStudentsNewRoute
+  AuthenticatedStudentsIndexRoute: typeof AuthenticatedStudentsIndexRoute
 }
 
 const AuthenticatedStudentsRouteChildren: AuthenticatedStudentsRouteChildren = {
   AuthenticatedStudentsIdRoute: AuthenticatedStudentsIdRoute,
   AuthenticatedStudentsNewRoute: AuthenticatedStudentsNewRoute,
+  AuthenticatedStudentsIndexRoute: AuthenticatedStudentsIndexRoute,
 }
 
 const AuthenticatedStudentsRouteWithChildren =