fix(protect): handle undefined and null values in model interfaces

[calvinbrewer]

Fixes an issue where the model interfaces don't handle undefined correctly. Now the model interfaces will handle both null and undefined values correctly

[Copilot]

Pull Request Overview

This PR extends model interface handling to cover undefined in addition to null, updating both single and bulk operations, and adds corresponding tests.

• Expand nullFields type and logic to treat undefined as a first‐class case
• Mirror changes in prepareBulkModelsForOperation
• Add unit tests for encryption/decryption with undefined
• Publish a changeset entry for the fix

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
packages/protect/src/ffi/model-helpers.ts	Allow nullFields to store undefined and adjust checks
packages/protect/tests/protect.test.ts	New tests for single and bulk operations handling undefined
.changeset/thirty-otters-cough.md	Document the fix for null/undefined handling (with typo)

Comments suppressed due to low confidence (1)

packages/protect/src/ffi/model-helpers.ts:131

• [nitpick] The variable name nullFields now holds both null and undefined values, which may be misleading; consider renaming it to something like nullishFields to clarify its purpose.

nullFields: Record<string, null | undefined>