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/api/tax-exemptions.ts

@@ -0,0 +1,28 @@
+import { queryOptions } from '@tanstack/react-query'
+import { api } from '@/lib/api-client'
+import type { TaxExemption } from '@/types/account'
+
+export const taxExemptionKeys = {
+  all: (accountId: string) => ['accounts', accountId, 'tax-exemptions'] as const,
+}
+
+export function taxExemptionListOptions(accountId: string) {
+  return queryOptions({
+    queryKey: taxExemptionKeys.all(accountId),
+    queryFn: () => api.get<{ data: TaxExemption[] }>(`/v1/accounts/${accountId}/tax-exemptions`),
+  })
+}
+
+export const taxExemptionMutations = {
+  create: (accountId: string, data: Record<string, unknown>) =>
+    api.post<TaxExemption>(`/v1/accounts/${accountId}/tax-exemptions`, data),
+
+  update: (id: string, data: Record<string, unknown>) =>
+    api.patch<TaxExemption>(`/v1/tax-exemptions/${id}`, data),
+
+  approve: (id: string) =>
+    api.post<TaxExemption>(`/v1/tax-exemptions/${id}/approve`, {}),
+
+  revoke: (id: string, reason: string) =>
+    api.post<TaxExemption>(`/v1/tax-exemptions/${id}/revoke`, { reason }),
+}