docs: add useGoogleAnalytics to api documentation (#25403)

docs/3.api/2.composables/use-google-analytics.md

@@ -0,0 +1,61 @@
+---
+title: useGoogleAnalytics
+description: useGoogleAnalytics allows you to load and initialize Google Analytics in your Nuxt app.
+links:
+  - label: Source
+    icon: i-simple-icons-github
+    to: https://github.com/nuxt/scripts-and-assets/blob/main/modules/nuxt-third-party-capital/src/runtime/composables/googleAnalytics.ts
+    size: xs
+---
+
+The `useGoogleAnalytics` composable function allows you to include [Google Analytics 4](https://developers.google.com/analytics/devguides/collection/ga4) in your Nuxt application.
+
+::callout
+If Google Tag Manager is already included in your application, you can configure Google Analytics directly using it, rather than including Google Analytics as a separate component. Refer to the [documentation](https://developers.google.com/analytics/devguides/collection/ga4/tag-options#what-is-gtm) to learn more about the differences between Tag Manager and gtag.js.
+::
+
+## Type
+
+```ts
+useGoogleAnalytics(options: ThirdPartyScriptOptions<GoogleAnalyticsOptions, GoogleAnalyticsApi>): ThirdPartyScriptApi<GoogleAnalyticsApi>
+```
+
+## Params
+
+An object containing the following options:
+
+| name | type   | description                     |
+|:-----|:-------|:--------------------------------|
+| id   | string | Google Analytics [measurement ID](https://support.google.com/analytics/answer/12270356). (required) |
+
+## Return values
+
+An object that contains a special `$script` property that gives you access to the underlying script instance.
+
+- `$script.waitForLoad`: A promise that resolves when the script is ready to use. It exposes `gtag` and `dataLayer`, which lets you interact with the API.
+
+::callout
+Learn more about [useScript](https://unhead.unjs.io/usage/composables/use-script).
+::
+
+## Minimal example
+
+```vue
+<script setup>
+useGoogleAnalytics({ id: 'GA-123456789-1' })
+</script>
+```
+
+## Example with custom event
+
+```vue
+<script setup>
+const { $script } = useGoogleAnalytics({
+  id: 'GA-123456789-1',
+})
+
+$script.waitForLoad().then(({ gtag }) => {
+  gtag('event', 'some_custom_event', { time: new Date() })
+})
+</script>
+```