feat(pos): add TypeScript types for pos.app.ready.data background target

Add DataTargetApi type and DataExtensionTargets interface for the new
persistent background extension target. DataTargetApi provides the full
POS API surface excluding UI-presenting APIs (Toast, Print, Camera,
PinPad). Background extensions that need UI should use companion targets.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: vctrchu

packages/ui-extensions/src/surfaces/point-of-sale/api.ts

@@ -13,6 +13,7 @@ export type {ActionApi, ActionApiContent} from './api/action-api/action-api';
 
 export type {StandardApi} from './api/standard/standard-api';
 export type {ActionTargetApi} from './api/action-target-api/action-target-api';
+export type {DataTargetApi} from './api/data-target-api/data-target-api';
 
 export type {
   CameraApi,

packages/ui-extensions/src/surfaces/point-of-sale/api/data-target-api/data-target-api.ts

@@ -0,0 +1,22 @@
+import {CartApi} from '../cart-api/cart-api';
+import {ConnectivityApi} from '../connectivity-api/connectivity-api';
+import {DeviceApi} from '../device-api/device-api';
+import {LocaleApi} from '../locale-api/locale-api';
+import {ProductSearchApi} from '../product-search-api/product-search-api';
+import {SessionApi} from '../session-api/session-api';
+import {StorageApi} from '../storage-api/storage-api';
+import type {I18n} from '../../../../api';
+
+/**
+ * API surface for non-rendering data extension targets.
+ */
+export type DataTargetApi<T> = {
+  extensionPoint: T;
+  i18n: I18n;
+} & SessionApi &
+  StorageApi &
+  LocaleApi &
+  ConnectivityApi &
+  DeviceApi &
+  ProductSearchApi &
+  CartApi;

packages/ui-extensions/src/surfaces/point-of-sale/extension-targets.ts

@@ -6,7 +6,9 @@ import {
 import {TransactionCompleteData} from './event/data/TransactionCompleteData';
 import {CartUpdateEventData} from './event/data/CartUpdateEventData';
 
-import type {RenderExtension} from '../../extension';
+import type {RenderExtension, RunnableExtension} from '../../extension';
+
+import type {DataTargetApi} from './api/data-target-api/data-target-api';
 
 import type {
   StandardApi,
@@ -43,6 +45,18 @@ export interface EventExtensionTargets {
   ) => Promise<BaseOutput>;
 }
 
+export interface DataExtensionTargets {
+  /**
+   * A persistent background extension that starts when POS loads and runs for
+   * the session's lifetime. Use this target to observe POS events without
+   * rendering UI.
+   */
+  'pos.app.ready.data': RunnableExtension<
+    DataTargetApi<'pos.app.ready.data'>,
+    undefined
+  >;
+}
+
 export interface RenderExtensionTargets {
   /**
    * Renders a single interactive tile component on the POS home screen's smart grid. The tile appears once during home screen initialization and remains persistent until navigation occurs. Use this target for high-frequency actions, status displays, or entry points to workflows that merchants need daily.
@@ -362,8 +376,10 @@ export interface RenderExtensionTargets {
 
 export interface ExtensionTargets
   extends RenderExtensionTargets,
-    EventExtensionTargets {}
+    EventExtensionTargets,
+    DataExtensionTargets {}
 
 export type RenderExtensionTarget = keyof RenderExtensionTargets;
 export type EventExtensionTarget = keyof EventExtensionTargets;
+export type DataExtensionTarget = keyof DataExtensionTargets;
 export type ExtensionTarget = keyof ExtensionTargets;