feat: warn admins when editing contractor profile/address after W-9 signing

[aaronlee777]

Summary

• Adds an SDK Alert (warning variant) above the Contractor Profile (admin edit surface) and Contractor Address forms when the contractor already has a signed W-9 on file.
• Alert copy signals to the admin that changing name/SSN/EIN or the mailing address will require re-collecting a new W-9.
• Introduces a small useContractorHasSignedW9(contractorId) Suspense hook that reads the documents endpoint and returns true iff the contractor has a W-9 with a signedAt timestamp. The presence of a signed W-9 naturally covers both the self_onboarding_review and onboarding_completed cases without threading state through the flow machine.
• Profile: alert only mounts in edit mode (mode === 'update' + resolved uuid), so create-mode never fetches documents.
• Address: contractorId is always required, so no gating needed.
• Self-onboarding contractor branch (SelfOnboardingContractorProfile) is intentionally left untouched.

Test plan

• npm run test -- --run src/components/Contractor/Profile src/components/Contractor/Address (111 passing, including 5 new W-9 warning cases)
• npx tsc --noEmit clean
• Manual admin review path: pull SDK dev app, load a contractor in self_onboarding_review state with a signed W-9, verify warning renders above both edit surfaces

JIRA: SDK-1029

🤖 Generated with Claude Code

[serikjensen]

Code is looking good! blocking since we still need confirmation from legal that this is the correct way forward

[serikjensen]

@cursoragent could you take a look at test failures on this one and resolve?

[cursor]

Perfect! I've fixed the test failures and pushed the changes. Here's what I did:

Fixed Issues

1. Added missing contractor documents mock - The new W9 warning component uses useContractorHasSignedW9() which fetches contractor documents via a Suspense hook. The renderEditForPostSaveStatus test helper was missing the documents endpoint mock, causing the component to hang during rendering. I added handleGetContractorDocuments(() => HttpResponse.json(buildContractorDocumentsList())) to the test setup.

2. Updated button text in test - The test was looking for a button labeled "Update Contractor", but the actual button text comes from the translation key buttons.update which is "Continue". I updated the test to use the correct button text.

Results

• All 26 tests in ContractorProfile.test.tsx now pass ✅
• All 33 tests in the Contractor Address component pass ✅
• TypeScript type check passes with no errors ✅
• Changes committed and pushed successfully

The CI should re-run with these fixes and the tests should pass.