FIELD-TYPE-GUARDS.md imports field type guards from wrong package in code examples

Documentation Issue

Summary:

The reference documentation for field type guards in tools/claude-plugin/skills/payload/reference/FIELD-TYPE-GUARDS.md currently imports guard functions like fieldAffectsData and fieldHasSubFields from payload, but these helpers are actually exported from payload/shared, which matches current usage throughout the repository. This can cause confusion for users copying the examples and leads to import errors or mismatches with the actual codebase.

Additional Details

• The location of the affected documentation is:
  • tools/claude-plugin/skills/payload/reference/FIELD-TYPE-GUARDS.md
  • (Potentially also: tools/claude-plugin/skills/payload/reference/FIELDS.md)
• Current examples use imports like:

  import type { Field } from 'payload'
  import { fieldHasSubFields } from 'payload'
  import { fieldAffectsData, fieldHasSubFields, fieldIsArrayType } from 'payload'
  

• Actual working usage should be:

  import type { Field } from 'payload'
  import { fieldHasSubFields } from 'payload/shared'
  import { fieldAffectsData, fieldHasSubFields, fieldIsArrayType } from 'payload/shared'
  

• This matches both the export source (packages/payload/src/exports/shared.ts) and existing usage in core packages (graphql, drizzle, UI, plugin-import-export, etc).

Suggested fix:

• Update all code samples in FIELD-TYPE-GUARDS.md (and optionally FIELDS.md) to use payload/shared for field guard helpers while keeping types imported from payload.
• This will help keep docs in sync with current code and prevent copy-paste confusion for users.

Reference conversation:

• See https://github.com/payloadcms/payload/blob/386805c34433dada690135010e62440b1f2b1006/tools/claude-plugin/skills/payload/reference/FIELD-TYPE-GUARDS.md for the current file.
• Discrepancy identified in user and repo usage, confirmed by semantic and code search.

Copilot conversation context: We found no open issues filing this discrepancy, but several export errors have affected users due to import/export mismatches (payload/shared, etc). This update would close a gap in the docs discovered during a code review.