feat: add multi-step invoice submission

[newmattock]

Fixes #15

Summary

• refactor the reusable invoice submission form into Invoice Details, Token & Rate, and Review & Submit steps
• add a progress indicator plus Back/Next navigation while preserving form state between steps
• keep the LP preview visible and add the final review breakdown with “You will receive” and “LP yield is” rows plus wallet confirmation prompt
• update submission and address-book tests for the stepped flow
• carry narrow current-main build fixes for governance status typing and related TypeScript compatibility issues

Validation

• npm test -- src/components/__tests__/SubmitInvoiceForm.test.tsx --reporter verbose
• npm test -- src/components/__tests__/SubmitInvoiceFormAddressBook.test.tsx --reporter verbose
• npm run lint -- app/governance/page.tsx src/utils/federation.ts src/utils/evidence.ts src/components/TokenSelector.tsx src/components/SubmitInvoiceForm.tsx src/components/StepIndicator.tsx src/components/__tests__/SubmitInvoiceForm.test.tsx src/components/__tests__/SubmitInvoiceFormAddressBook.test.tsx
• npm run build
• git diff --check
• local smoke: curl -I http://localhost:3029/submit returned HTTP/1.1 200 OK

Note: attempted an additional Playwright browser smoke, but the local Playwright Chromium binary was not installed in this Codex environment.