Support UI extensions

[pbennett1-godaddy]

Summary

Adds Phase 1 checkout UI extension runtime support to @godaddy/react.

This introduces a production-shaped bridge runtime that can discover enabled store UI extensions, load deterministic CDN-hosted DOM bundles, and mount them into checkout target slots without blocking
checkout. Phase 1 intentionally supports trusted in-page DOM bundles while preserving runtime seams for a future worker/SDK-based UI extension architecture.

Key goals addressed:

• Load enabled UI extensions for a target from checkout-api or provided checkout session app data.
• Build deterministic extension bundle URLs from cdnUrl, target, applicationId, and releaseId.
• Mount each extension into a host-owned checkout target container.
• Pass only minimized checkout context plus consumer-owned initialProps.
• Keep checkout resilient when extension loading, registration, mount, update, or unmount fails.
• Add structured runtime errors for observability.
• Keep debug behavior diagnostic-only through GoDaddyProvider debug logging, without changing runtime behavior.

Changeset

• Changeset added (docs)

Test Plan

Validated locally with:

pnpm --filter @godaddy/react typecheck                                                                                                                                                                  
pnpm --filter @godaddy/react test -- --runInBand                                                                                                                                                        
pnpm --filter @godaddy/react lint                                                                                                                                                                       
pnpm --filter @godaddy/react build                                                                                                                                                                      

Results:

• Typecheck passes.
• React package test suite passes.
• Biome lint/check passes.
• React package build succeeds, including the new @godaddy/react/ui-extensions subpath export.

Additional coverage added for:

• Deterministic UI extension script URL construction.
• Missing required script URL fields.
• DOM bundle registration and mount lifecycle.
• Invalid DOM bundle contracts.
• Runtime update and unmount lifecycle.
• Unmount-before-script-load behavior.
• Queued updates while an extension bundle is still loading.
• Target behavior with provided app data.
• Target behavior with checkout-api response data.
• Provider debug mode continuing to render runtime containers instead of JSON.
• Grouping multiple UI extensions by target without duplicating app entries.

[changeset-bot]

🦋 Changeset detected

Latest commit: 1ceac08

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@godaddy/react	Patch
nextjs	Patch

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