fix(cloudinary): persist clientUploadContext fields on Payload 3.82+

[jhb-dev]

Summary

Restores persistence of cloudinaryPublicId and url for client-side uploads after the upstream regression in @payloadcms/plugin-cloud-storage v3.82+.

Root cause

In Payload 3.82, @payloadcms/plugin-cloud-storage changed its afterChange hook to skip adapter.handleUpload(...) whenever the incoming file carries a clientUploadContext (upstream PR #16115). For stateless backends like S3 this is fine — the file is already at a deterministic key. But this plugin used handleUpload to copy publicId / secureUrl from clientUploadContext into the doc's cloudinaryPublicId and url fields. With that call skipped:

• cloudinaryPublicId is never persisted →
• adapter.generateURL returns undefined →
• data.url ends up unset →
• Admin falls back to /api/{collection}/file/{filename} →
• Payload's local-file fallback errors with "missing on disk".

Fix

Adds a collection-level beforeChange hook on each Cloudinary-enabled collection. The hook reads req.file.clientUploadContext and writes both cloudinaryPublicId and url directly into data. Collection-level hooks run after field-level hooks, so this also overrides the URL field whose beforeChange saw no cloudinaryPublicId.

Also drops the now-dead if (clientUploadContext) branch from src/handleUpload.ts — upstream filters those files out before calling the adapter, so the branch is unreachable.

Trade-off — this is a workaround

This restores correctness without depending on upstream. The deeper problem is an upstream API contract violation: the HandleUpload type still declares clientUploadContext as a parameter, but the runtime filters those calls away (afterChange.js:35). An alternate PR (refactor the plugin to be stateless like @payloadcms/storage-s3) is opened separately.

Test plan

• New src/index.test.ts reproduces the bug: runs the plugin and exercises the resulting collection's beforeChange hook with a simulated req.file.clientUploadContext; asserts data.cloudinaryPublicId and data.url are set. Failed before the fix, passes after.
• pnpm typecheck clean.
• pnpm lint clean.
• pnpm build produces a clean dist/ with no *.test.* files.
• End-to-end check in cloudinary/dev — start the dev app, upload an image to the images collection (which uses disablePayloadAccessControl: true + clientUploads: true), confirm the doc lands with cloudinaryPublicId and url populated and the admin preview renders.

Adds vitest scaffolding

This plugin had no test setup; the PR mirrors what vercel-deployments already does: vitest devDep, test / test:watch scripts, vitest.config.ts, and a tsconfig.build.json that excludes test files from the published build (matching swc's --ignore flag).