Add locale parameter support for blueprint translations

[epeicher]

Related issues

• Fixes STU-1154

Proposed Changes

This PR adds locale parameter support to the blueprints endpoint to ensure blueprint descriptions are returned in the user's configured language.

• Modified the getBlueprints API query to accept and pass an optional locale parameter to the WordPress.com endpoint
• Updated blueprint components to retrieve the user's configured locale from the i18n store and pass it to the API

Testing Instructions

1. Apply the following changes to your sandbox 199274-ghe-Automattic/wpcom
2. Sandbox the public-api
3. Start the app with npm start
4. Change your system language or app locale to a non-English language (e.g., Spanish, French, German)
5. Navigate to "Add New Site"
6. Select "Create from a blueprint" option
7. Verify that the blueprint descriptions appear in the selected language
8. Test with multiple different locales to ensure the translation works correctly
9. Verify that if locale is not set, the API still works with the default English descriptions

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[Copilot]

Pull request overview

This PR adds locale parameter support to the blueprints API endpoint to enable blueprint descriptions to be returned in the user's configured language. The implementation ensures that when users view available blueprints, they see descriptions translated to their selected language preference.

• Modified the getBlueprints API query to accept an optional locale parameter
• Updated blueprint-consuming components to retrieve and pass the user's locale from the i18n store

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/stores/wpcom-api.ts	Updated getBlueprints endpoint to accept optional locale parameter and append it to the API request URL
src/modules/add-site/index.tsx	Added useI18nLocale hook import and passed locale to useGetBlueprints
src/modules/add-site/components/blueprints.tsx	Added useI18nLocale hook import and passed locale to useGetBlueprints for refetch functionality

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[gcsecsey]

Thanks for working on these changes @epeicher! 👍

This LGTM and works well when testing different locales.

English	German	Italian