docs: omit implementation details from hooks reference

[serikjensen]

Summary

Tightens the hook reference docs to focus on what partners need to build forms, removing implementation-detail leaks that don't help integrators and that previously could mislead readers into wiring forms in non-recommended ways.

Changes

• Removed the Advanced: Fields Metadata section from hooks.md so partners aren't steered toward consuming fieldsMetadata directly. Field components consume metadata internally; the recommended path is Fields (with FieldComponent for UI overrides).
• Reworded the Fields.Ssn section to describe the masked placeholder + auto-waived REQUIRED rule behaviorally instead of via fieldsMetadata.ssn.hasRedactedValue.
• Replaced internal symbols with behavioral descriptions: NAME_REGEX (Employee Details), FLSA_OVERTIME_SALARY_LIMIT (Compensation), rev_2020_w4 (Federal Taxes).
• Stripped schema-builder vocabulary ('never' / 'always' / "predicate", "schema declares/enforces") from Pay Schedule, Compensation, and hooks.md in favor of partner-facing language.
• Dropped the internal Rule column from the Compensation required-fields table; the remaining columns convey the same partner-relevant info.
• Removed raw HTTP endpoint paths (e.g. GET /v1/work_addresses/{work_address_uuid}, POST) from Work Address mode descriptions in favor of mode-only language.

What was intentionally preserved:

• fieldsMetadata in return-type signatures and the SignEmployeeFormFieldsMetadata row in the Exported Types table — they accurately describe the public return shape without prescribing direct consumption.
• react-hook-form / Zod / UseFormReturn references — partner-relevant framework context, especially for the Advanced: Hook Form Internals escape hatch.
• Cross-references to other public hooks (e.g. useCurrentWorkAddressForm, useWorkAddressManagement).

Testing

• Docs-only change; no code touched.
• Re-grepped `docs/hooks/` to confirm no remaining `NAME_REGEX`, `FLSA_OVERTIME_SALARY_LIMIT`, `rev_2020_w4`, `/v1/`, `'never'`/`'always'` requiredness, or "predicate rule" references outside legitimate framework/behavioral usage.
• Visual review of each modified `docs/hooks/*.md` file confirmed updates read cleanly.

Made with Cursor