Remove the standalone accelerated checkouts Swift sample

[kieran-osgood-shopify]

What changes are you making?

The standalone accelerated checkouts Swift sample duplicated the main demo and required a shared Xcode workspace even though only one maintained demo is needed.

• Moves the unique Apple Pay, buyer contact, locale, supported-country, and logging settings into a dedicated pushed screen in CheckoutKitSwiftDemo.
• Applies accelerated checkout configuration consistently to cart and product flows while preserving the iOS 15 deployment target.
• Deletes ShopifyAcceleratedCheckoutsApp and the obsolete Samples.xcworkspace.
• Points Swift development, Apollo, CI, E2E, and release builds directly at CheckoutKitSwiftDemo.xcodeproj.
• Keeps the sample dependency pins in CheckoutKitSwiftDemo/Package.resolved and copies them into the generated project.

Previously, dev swift open opened the shared samples workspace and accelerated checkout configuration lived in the separate app. It now opens the consolidated demo project directly.

How to test

GIVEN this PR is checked out and dev up has generated the Swift sample configuration

WHEN the reviewer runs dev swift open

THEN Xcode should open CheckoutKitSwiftDemo.xcodeproj directly, and the CheckoutKitSwiftDemo scheme should build and run without Samples.xcworkspace

---

GIVEN CheckoutKitSwiftDemo is running on iOS 16 or newer with valid Storefront and Apple Pay merchant configuration

WHEN the reviewer opens Settings, selects Configure Accelerated Checkouts, and changes the accelerated checkout language, contact requirements, buyer email or phone, supported shipping countries, and log level

THEN a dedicated Accelerated Checkouts screen should be pushed onto the navigation stack, and those choices should remain selected after leaving and reopening the screen and should be applied to accelerated checkout controls in the product and cart flows without a missing-configuration error

---

Before you merge

Important

• I've added tests to support my implementation
• I have read and agree with the Contribution Guidelines
• I have read and agree with the Code of Conduct
• I've updated the relevant platform README (platforms/swift/README.md and/or platforms/android/README.md)

---

Releasing a new Swift version?

• I have bumped the version in ShopifyCheckoutKit.podspec
• I have bumped the version in platforms/swift/Sources/ShopifyCheckoutKit/ShopifyCheckoutKit.swift
• I have updated the SwiftPM/CocoaPods version snippets in platforms/swift/README.md (major version only)

Releasing a new Embedded Checkout Protocol version?

• I have bumped embeddedCheckoutProtocolAndroid in platforms/android/gradle/libs.versions.toml
• I have updated protocol/languages/kotlin/embedded-checkout-protocol/api/embedded-checkout-protocol.api if the public API changed

Releasing a new Android version?

• I have bumped checkoutKitAndroid in platforms/android/gradle/libs.versions.toml
• I have updated the Gradle/Maven version snippets in platforms/android/README.md

Tip

See the Contributing documentation for the full release process per platform.