[jdjioe5-cpu]

Summary

Closes #15. Fulfills Roadmap row M1-40 (Phase 1, M0 Validate, Priority P1).

This PR introduces a comprehensive boundary-fixture corpus for the registry validator in fixtures/boundary/:

• Valid Boundary Fixtures (valid/):
  • 0-decimal-jpy.json: 0-decimal currency (JPY, Japan)
  • 3-decimal-bhd.json: 3-decimal currency (BHD, Bahrain)
  • non-latin-japanese.json: Non-Latin Unicode script in display_name (Japanese)
  • rtl-arabic.json: Right-to-Left script in display_name (Arabic)
  • diacritics-french.json: Multi-word French name with diacritics
  • slug-exact-80-chars.json: Slug at exactly the 80-character maximum limit
• Rejection Boundary Fixtures (invalid/):
  • slug-81-chars.json: Rejection on exceeding 80 characters (81 chars)
  • payout-address-short-55.json: Rejection on wrong address length (55 chars)
  • payout-address-lowercase.json: Rejection on lowercase address character
  • payout-address-swapped-prefix.json: Rejection on invalid prefix (S instead of G/C)
  • directory-country-mismatch.json: Rejection on file placed in wrong country folder
  • attester-unauthorized-country.json: Rejection on attester not authorized for target country
  • duplicate-slug-cross-country.json: Rejection on duplicate slug across different countries
• Test Suite: Added 13 dedicated unit test cases in scripts/boundary.test.ts asserting exact error message patterns and confirming canonical UTF-8 hashing stability. Total 29/29 tests green.
• Corpus Documentation: Created fixtures/boundary/README.md.
• Roadmap: Marked M1-40 as DONE in ROADMAP.md with Changelog entry.

Non-Personal Data & Multi-Country Guarantee

• Zero real institutions, zero personal data, and zero live wallets.
• Covers multiple countries (Japan, Bahrain, Egypt, France, Kenya, Philippines, Ghana) demonstrating the country-agnostic core (Hard Rule 11).
• Live payees/, attesters/, and supported-countries.json remain completely untouched.

Real Command Outputs Executed

$ pnpm lint
> biome check .
Checked 13 files in 13ms. No fixes applied.

$ pnpm typecheck
> tsc -p tsconfig.json
(exit 0, 0 errors)

$ pnpm test
> vitest run
 Test Files  2 passed (2)
      Tests  29 passed (29)
   Duration  282ms

$ pnpm validate
> tsx scripts/validate.ts
3 payee file(s) checked, 0 problem(s)

$ pnpm hash fixtures/boundary/valid/slug-exact-80-chars.json
payee_id  411268ec536774628e9cfd10ba76e835ee5f52990abc7143e62b8c410c40d4ff
meta_hash b2245ab73fecf5d7ceb597338b6a0be869c81d805c75d39f5a8bc11bef8ae818