Add shipping options to Cart API responses (6271)

[stracker-phil]

Description

Extends and refactors the CartResponse class to address the following items:

1. Provide a new shipping_options array in the cart response

   • This response is generated by inspecting the WC()->shipping() data
   • Assigned to the cart response via a new setter shipping_options()
   • When the WC object has no shipping options, an empty array is returned

2. Consolidated the CartResponse classes, implementing the same factory-method-logic which we use in most other parts of the module

   • Three static factory methods in the main class
   • Same pattern from ValidationIssue or in ResolutionOption
   • Note how all classes have a private constructor; also applied to the CartResponse
   • Also dropped the now obsolete classes: NewCartResponse and PaidCartResponse

3. Refactored the ResponseFactory, which still is the only place that creates new CartResponse instances

4. Extended (and adjusted) the test suite to cover the response expectations more thoroughly

[github-actions]

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What's included:

• ✅ WordPress (latest)
• ✅ WooCommerce (latest)
• ✅ PayPal Payments plugin v4.0.2-pr4306-25006210625-gc33a8db (built from this PR)

Login credentials:

• Username: admin
• Password: password

Plugin Details:

• Version: 4.0.2-pr4306-25006210625-gc33a8db
• Commit: c8e3ca6
• Artifact: woocommerce-paypal-payments-4.0.2-pr4306-25006210625-gc33a8db

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_{🤖 Auto-generated for commit c8e3ca6 • Last updated: 2026-04-27T16:14:13.637Z}

[Narek13]

Thanks a lot for working on this. LGTM, although haven't tested. Just some questions/doubts regarding ShippingOptionsBuilder

[Narek13]

Thanks for the clarifications. Looks good to me.