feat(brand): add brand sort order and drag-to-reorder

Add a sort_order column to brands with a migration, expose a
PUT /api/tenant/brands/order reorder endpoint, and wire the
admin-web BrandsView with drag-and-drop reordering plus i18n.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/admin-web/src/lib/api.ts

@@ -10,6 +10,7 @@ import type {
   AuthTokens,
   Brand,
   BrandLibrarySummary,
+  BrandReorderRequest,
   BrandRequest,
   ChangePasswordRequest,
   ClassifiedQuestion,
@@ -1158,6 +1159,9 @@ export const brandsApi = {
   remove(id: number) {
     return apiClient.remove<null>(`/api/tenant/brands/${id}`)
   },
+  reorder(payload: BrandReorderRequest) {
+    return apiClient.put<Brand[], BrandReorderRequest>('/api/tenant/brands/order', payload)
+  },
   listKeywords(brandId: number) {
     return apiClient.get<Keyword[]>(`/api/tenant/brands/${brandId}/keywords`)
   },