fix(payment): resolve PR audit issues

- Add payment navigation to AppSidebar (user orders + admin payment menu group with collapse)
- Add 5 missing nav i18n keys (myOrders, orderManagement, paymentDashboard, paymentConfig, paymentPlans)
- Renumber payment migrations 090-100 → 092-102 to avoid conflict with upstream 090/091
- Remove non-payment sora_client_enabled change, restore upstream purchase_subscription fields
- Remove extra 'data' from SettingsTab type union

frontend/src/api/admin/settings.ts

@@ -38,7 +38,8 @@ export interface SystemSettings {
   doc_url: string
   home_content: string
   hide_ccs_import_button: boolean
-  sora_client_enabled: boolean
+  purchase_subscription_enabled: boolean
+  purchase_subscription_url: string
   backend_mode_enabled: boolean
   custom_menu_items: CustomMenuItem[]
   custom_endpoints: CustomEndpoint[]
@@ -155,6 +156,8 @@ export interface UpdateSettingsRequest {
   doc_url?: string
   home_content?: string
   hide_ccs_import_button?: boolean
+  purchase_subscription_enabled?: boolean
+  purchase_subscription_url?: string
   backend_mode_enabled?: boolean
   custom_menu_items?: CustomMenuItem[]
   custom_endpoints?: CustomEndpoint[]