[owenshen0907]

Why

Fixes #552. Form layout validation currently accepts GROUP, SUBTABLE, STATUS, STATUS_ASSIGNEE, and CATEGORY as fields inside a row. Invalid layouts reach kintone and produce an opaque CB_VA01 error.

What

Restrict the shared field schema to the 26 types documented for Update Form Layout and Get Form Layout. Top-level group and subtable layouts remain supported.

Regressions cover the documented types, invalid types in nested layouts, group-content stripping, and the update input/get output schemas.

How to test

• The new focused test file has 11 failures against the original implementation and passes all 38 tests after the fix.
• pnpm test --run: 826 tests pass.
• pnpm typecheck, pnpm lint, pnpm build, pnpm check:mcpb, and pnpm license:analyze pass.
• Tested with Node.js 24.16.0 and the repository-pinned pnpm 10.34.5; dependencies were installed from the frozen lockfile with lifecycle scripts disabled.
• Live kintone E2E tests were not run because they require an account and test app credentials. Docker builds were not run.

Checklist

• Updated documentation if it is required (no user documentation change needed).
• Added tests if it is required.
• Passed pnpm lint and pnpm test on the root directory.

AI assistance was used for this contribution.