Add child route (sub-area) management to route detail page

Shows a sub-areas section below encounters with add/delete support
and links to navigate to child route details.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/admin/AdminRouteDetail.tsx

@@ -2,16 +2,22 @@ import { useMemo, useState } from 'react'
 import { useParams, Link, useNavigate } from 'react-router-dom'
 import { AdminTable, type Column } from '../../components/admin/AdminTable'
 import { RouteEncounterFormModal } from '../../components/admin/RouteEncounterFormModal'
+import { RouteFormModal } from '../../components/admin/RouteFormModal'
+import { DeleteConfirmModal } from '../../components/admin/DeleteConfirmModal'
 import { useGame, useRoutePokemon } from '../../hooks/useGames'
 import {
   useAddRouteEncounter,
   useUpdateRouteEncounter,
   useRemoveRouteEncounter,
+  useCreateRoute,
+  useDeleteRoute,
 } from '../../hooks/useAdmin'
 import type {
+  Route,
   RouteEncounterDetail,
   CreateRouteEncounterInput,
   UpdateRouteEncounterInput,
+  CreateRouteInput,
 } from '../../types'
 
 export function AdminRouteDetail() {
@@ -26,9 +32,13 @@ export function AdminRouteDetail() {
   const addEncounter = useAddRouteEncounter(rId)
   const updateEncounter = useUpdateRouteEncounter(rId)
   const removeEncounter = useRemoveRouteEncounter(rId)
+  const createRoute = useCreateRoute(gId)
+  const deleteRoute = useDeleteRoute(gId)
 
   const [showCreate, setShowCreate] = useState(false)
   const [editing, setEditing] = useState<RouteEncounterDetail | null>(null)
+  const [showCreateChild, setShowCreateChild] = useState(false)
+  const [deletingChild, setDeletingChild] = useState<Route | null>(null)
 
   const sortedRoutes = useMemo(
     () => [...(game?.routes ?? [])].sort((a, b) => a.order - b.order),
@@ -42,6 +52,15 @@ export function AdminRouteDetail() {
       ? sortedRoutes[currentIndex + 1]
       : undefined
 
+  const childRoutes = useMemo(
+    () => (game?.routes ?? []).filter((r) => r.parentRouteId === rId).sort((a, b) => a.order - b.order),
+    [game?.routes, rId],
+  )
+
+  const nextChildOrder = childRoutes.length > 0
+    ? Math.max(...childRoutes.map((r) => r.order)) + 1
+    : (route?.order ?? 0) * 10 + 1
+
   const columns: Column<RouteEncounterDetail>[] = [
     {
       header: 'Pokemon',
@@ -171,6 +190,69 @@ export function AdminRouteDetail() {
           isDeleting={removeEncounter.isPending}
         />
       )}
+
+      {/* Sub-areas */}
+      <div className="mt-8">
+        <div className="flex justify-between items-center mb-3">
+          <h3 className="text-lg font-semibold">Sub-areas ({childRoutes.length})</h3>
+          <button
+            onClick={() => setShowCreateChild(true)}
+            className="px-3 py-1.5 text-sm font-medium rounded-md bg-blue-600 text-white hover:bg-blue-700"
+          >
+            Add Sub-area
+          </button>
+        </div>
+        {childRoutes.length === 0 ? (
+          <p className="text-sm text-gray-500 dark:text-gray-400">No sub-areas for this route.</p>
+        ) : (
+          <div className="border rounded-md dark:border-gray-700 divide-y dark:divide-gray-700">
+            {childRoutes.map((child) => (
+              <div key={child.id} className="flex items-center justify-between px-4 py-2">
+                <Link
+                  to={`/admin/games/${gId}/routes/${child.id}`}
+                  className="text-blue-600 dark:text-blue-400 hover:underline"
+                >
+                  {child.name}
+                </Link>
+                <button
+                  onClick={() => setDeletingChild(child)}
+                  className="text-sm text-red-600 dark:text-red-400 hover:underline"
+                >
+                  Delete
+                </button>
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+
+      {showCreateChild && (
+        <RouteFormModal
+          nextOrder={nextChildOrder}
+          onSubmit={(data) =>
+            createRoute.mutate(
+              { ...data, parentRouteId: rId } as CreateRouteInput,
+              { onSuccess: () => setShowCreateChild(false) },
+            )
+          }
+          onClose={() => setShowCreateChild(false)}
+          isSubmitting={createRoute.isPending}
+        />
+      )}
+
+      {deletingChild && (
+        <DeleteConfirmModal
+          title={`Delete "${deletingChild.name}"?`}
+          message="This will permanently delete this sub-area and all its encounters."
+          onConfirm={() =>
+            deleteRoute.mutate(deletingChild.id, {
+              onSuccess: () => setDeletingChild(null),
+            })
+          }
+          onCancel={() => setDeletingChild(null)}
+          isDeleting={deleteRoute.isPending}
+        />
+      )}
     </div>
   )
 }

frontend/src/types/admin.ts

@@ -19,6 +19,7 @@ export interface UpdateGameInput {
 export interface CreateRouteInput {
   name: string
   order: number
+  parentRouteId?: number | null
   pinwheelZone?: number | null
 }