Add accounts UI with list, create, edit, detail tabs for all sub-entities

Accounts list with paginated table, search, sort. Account detail page with
tabs for members, payment methods, tax exemptions, and processor links.
All sub-entities have create/edit dialogs and delete actions. Forms use
shared Zod schemas via react-hook-form.

packages/admin/src/routes/_authenticated/accounts/new.tsx

@@ -0,0 +1,33 @@
+import { createFileRoute, useNavigate } from '@tanstack/react-router'
+import { useMutation, useQueryClient } from '@tanstack/react-query'
+import { accountMutations, accountKeys } from '@/api/accounts'
+import { AccountForm } from '@/components/accounts/account-form'
+import { toast } from 'sonner'
+
+export const Route = createFileRoute('/_authenticated/accounts/new')({
+  component: NewAccountPage,
+})
+
+function NewAccountPage() {
+  const navigate = useNavigate()
+  const queryClient = useQueryClient()
+
+  const mutation = useMutation({
+    mutationFn: accountMutations.create,
+    onSuccess: (account) => {
+      queryClient.invalidateQueries({ queryKey: accountKeys.lists() })
+      toast.success('Account created')
+      navigate({ to: '/accounts/$accountId', params: { accountId: account.id } })
+    },
+    onError: (err) => {
+      toast.error(err.message)
+    },
+  })
+
+  return (
+    <div className="space-y-6">
+      <h1 className="text-2xl font-bold">New Account</h1>
+      <AccountForm onSubmit={mutation.mutate} loading={mutation.isPending} />
+    </div>
+  )
+}