Update platform SDKs, protocol compatibility, and release tooling

[markmur]

Updates the platform SDKs and Embedded Checkout Protocol models, and adds per-platform release notes and versioning tooling.

• Extract Android checkout into a feature module bundled in the existing com.shopify:checkout-kit artifact. Public imports move to com.shopify.checkoutkit.checkout, with updated resources, samples, and publication checks.
• Introduce Swift appearance-owned color palettes, fix SwiftUI swipe-dismissal callbacks, and make protocol-routing APIs implementation details. Preserve the previous SwiftUI checkout names through deprecated compatibility aliases.
• Upgrade the React Native workspace and sample to 0.87.1, update dependencies, and configure the iOS SDK on the main actor.
• Update protocol model construction and preserve unknown string values, with regenerated API baselines and consumer compatibility checks.
• Add per-platform Changesets tooling and changelogs, improve package-size job selection, and support explicit device selection in local development commands.

Android imports, Swift appearance configuration and protocol-routing APIs, and direct protocol-model construction require migration. The accompanying documentation describes the new APIs. Existing native dependency pins remain unchanged; this PR does not publish packages or create release tags.

[github-actions]

Coverage Report

Status	Platform / target	Lines	Branches	Functions	Report
✅	Web	97.57%	86.35%	96%	Full report
✅	React Native	95.08%	89.13%	100%	Full report
✅	Embedded Checkout Protocol (TS)	94.51%	89.06%	91.67%	Full report

[bitrise]

Bitrise builds

E2E · iOS CI

Install this build

Open Tophat, select your target device, then click Install. Links open on the Mac running Tophat.

SDK	Install
React Native	Install with Tophat
Swift	Install with Tophat
Kotlin	Install with Tophat

Checkout Kit E2E results

Status	Tags	Target	Platform	OS version tag	Device
✅	launch, checkout-presentation, checkout-completion, buyer-identity	react-native	ios	latest	iPhone 15 iOS 27 Beta
✅	launch, checkout-presentation, checkout-completion, buyer-identity	react-native	android	latest	Google Pixel 9 Android 17.0
❌	launch, checkout-presentation, checkout-completion, buyer-identity, preload	kotlin	android	latest	Google Pixel 9 Android 17.0
✅	launch, checkout-presentation, checkout-completion, buyer-identity, preload	swift	ios	latest	iPhone 15 iOS 27 Beta

Failures

Caution

If you believe an assertion is flaky, please raise a ticket in the #checkout-kit-devs channel so it can be addressed.

BrowserStack artifacts require BrowserStack access. Sign in to BrowserStack App Automate before opening artifact links.

Android — kotlin

Test	Status	Artifacts
./tests/shared/checkout-guest	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/checkout-guest_bstackretry1	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/native-preload-ready	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/native-preload-ready_bstackretry1	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/checkout-hardcoded-buyer-identity	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/checkout-hardcoded-buyer-identity_bstackretry1	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/checkout-present-and-close	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log
./tests/shared/checkout-present-and-close_bstackretry1	❌	BrowserStack · Video · Screenshot · Maestro commands · Maestro log

[github-actions]

Bundle Size Budgets

Budget	Size	Limits	Result
Web JavaScript (uncompressed)	35.81 KiB (0 B)	35 KiB soft / 50 KiB hard	➖ Above budget; no increase
React Native npm package (gzip)	120.83 KiB (+186 B)	130 KiB soft / 150 KiB hard	✅ Within budget
Android AAR package (ZIP)	424.24 KiB (+1.98 KiB)	450 KiB soft / 500 KiB hard	✅ Within budget

Bundle and package size

Web bundle sizes cover shipped runtime JavaScript. Package sizes cover the full published archive, including any source maps, declarations, and documentation it contains.

Platform	Measurement	Compression	Base	Head	Delta
Web	JavaScript bundle	Uncompressed	35.8 KiB	35.8 KiB	0 B
Web	JavaScript bundle	gzip	11.2 KiB	11.2 KiB	0 B
Web	npm package (.tgz)	gzip	100.1 KiB	99.9 KiB	-184 B
React Native	npm package (.tgz)	gzip	120.6 KiB	120.8 KiB	+186 B
Android	Library package (.aar)	ZIP	422.3 KiB	424.2 KiB	+2.0 KiB

Web package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
dist/chunks/shopify-checkout.js.map	267.6 KiB	267.0 KiB	-650 B
dist/custom-elements.json	54.6 KiB	54.6 KiB	0 B
dist/index.d.ts	46.9 KiB	46.9 KiB	+80 B
dist/chunks/shopify-checkout.js	35.4 KiB	35.4 KiB	0 B
README.md	25.0 KiB	25.0 KiB	0 B
package.json	4.3 KiB	4.3 KiB	+1 B
LICENSE	1.1 KiB	1.1 KiB	0 B
dist/shopify-checkout.js.map	741 B	741 B	0 B
dist/index.js	255 B	255 B	0 B
dist/shopify-checkout.js	156 B	156 B	0 B
dist/shopify-checkout.d.ts	33 B	33 B	0 B

React Native package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
node_modules/@shopify/checkout-kit-protocol/src/generated/Models.ts	108.7 KiB	108.2 KiB	-562 B
node_modules/@shopify/checkout-kit-protocol/src/generated/Models.d.ts	73.1 KiB	73.2 KiB	+176 B
lib/index.cjs	52.8 KiB	52.8 KiB	-23 B
lib/index.js	51.9 KiB	51.9 KiB	-23 B
README.md	43.6 KiB	43.7 KiB	+36 B
lib/index.cjs.map	28.1 KiB	28.1 KiB	-33 B
lib/index.js.map	27.9 KiB	27.9 KiB	-37 B
lib/index.d.ts	24.6 KiB	24.6 KiB	0 B
android/src/main/java/com/shopify/reactnative/checkoutkit/ShopifyCheckoutKitModule.java	17.7 KiB	17.7 KiB	0 B
ios/ShopifyCheckoutKit.swift	14.8 KiB	15.4 KiB	+651 B
ios/AcceleratedCheckoutButtons.swift	14.8 KiB	14.8 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/ProtocolNotifications.ts	9.7 KiB	9.7 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/protocol_codec_runtime.ts	7.9 KiB	7.9 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/ProtocolRenameMap.ts	7.9 KiB	7.9 KiB	0 B
android/src/main/java/com/shopify/reactnative/checkoutkit/CustomCheckoutListener.java	6.2 KiB	6.2 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/generated/ProtocolNotifications.d.ts	5.7 KiB	5.7 KiB	0 B
ios/ShopifyCheckoutKit.mm	5.1 KiB	5.1 KiB	0 B
package.json	4.5 KiB	4.5 KiB	+38 B
android/build.gradle	4.1 KiB	4.1 KiB	0 B
node_modules/@shopify/checkout-kit-protocol/src/client.ts	3.6 KiB	3.6 KiB	0 B
…and 37 smaller files

Android package files (uncompressed)

These are uncompressed file sizes; they do not sum to the compressed package size above.

File	Base	Head	Delta
classes.jar	450.5 KiB	459.2 KiB	+8.7 KiB
res/layout/checkout_view_content.xml	2.6 KiB	2.6 KiB	-1 B
res/layout/checkout_sheet_content.xml	2.0 KiB	2.0 KiB	+38 B
res/values/values.xml	1.3 KiB	1.4 KiB	+27 B
R.txt	1.2 KiB	1.2 KiB	+21 B
AndroidManifest.xml	922 B	922 B	0 B
proguard.txt	798 B	826 B	+28 B
res/drawable/close.xml	431 B	—	-431 B
res/drawable/checkout_close.xml	—	431 B	+431 B
res/menu/checkout_menu.xml	354 B	351 B	-3 B
META-INF/com/android/build/gradle/aar-metadata.properties	157 B	179 B	+22 B
META-INF/MANIFEST.MF	—	25 B	+25 B

How sizes are measured

Measured from the PR base SHA and PR head SHA. Web bundle rows sum shipped .js, .mjs, and .cjs files under dist/, excluding source maps and declarations. The gzip bundle size sums files compressed individually with gzip -n -9. npm package sizes are gzip-compressed .tgz archives; Android AAR sizes are ZIP archives. Package sizes are not final app binary sizes.