Add cleanup hook helpers

[rjnevins]

/claim avajs#928

Summary

• Add cleanup hook helpers that run before and after tests
• Kept the patch narrow and aligned with the existing API/export shape.
• Avoided new runtime dependencies unless already present or required.

Issue Reproduction

• Local reproduction for Make it easier to write reliable cleanup tasks avajs/ava#928 encoded in test/create-chain/test.js: cleanup()/cleanupEach() should register matching before + after.always hooks, preserve serial, and skip both generated hooks.

Fix Verification

• node module-level cleanup chain smoke passed
• npx xo lib/create-chain.js test/create-chain/test.js
• npx tsd --files test-types/module/conditional-chains.ts
• npx tsc --noEmit
• git diff --check

Note: direct npx tap test/create-chain/test.js could not run locally because this machine has Node v25.9.0, while AVA supports ^22.20, ^24.12, or >=26.

Commands Run

• node -e "import('./lib/create-chain.js').then(...)"
• npx xo lib/create-chain.js test/create-chain/test.js
• npx tsd --files test-types/module/conditional-chains.ts
• npx tsc --noEmit
• git diff --check

Notes

• No payment details included.
• IssueHunt-funded issue Make it easier to write reliable cleanup tasks avajs/ava#928 remains open; no active open competing PR found during live check.