Function mapCategorizedTypeToEntityType

mapCategorizedTypeToEntityType(
categoryType: string,
subtype: string | null,
): OcfEntityType | null
Map categorized OCF type/subtype to OcfEntityType.

OCF data may be organized into categories:
- Direct types: STAKEHOLDER, STOCK_CLASS, STOCK_PLAN as the category
- Object subtypes: category='OBJECT', actual type in subtype
- Transaction subtypes: category='TRANSACTION', actual type in subtype (TX_ prefix)
Parameters
- categoryType: string
  The OCF category (STAKEHOLDER, OBJECT, TRANSACTION, etc.)
- subtype: string | null
  The subtype for OBJECT and TRANSACTION categories
Returns OcfEntityType | null
The corresponding OcfEntityType, or null if not supported
Example
```
mapCategorizedTypeToEntityType('STAKEHOLDER', null); // 'stakeholder'
mapCategorizedTypeToEntityType('DOCUMENT', null); // 'document' (direct type)
mapCategorizedTypeToEntityType('OBJECT', 'DOCUMENT'); // 'document' (categorized)
mapCategorizedTypeToEntityType('TRANSACTION', 'TX_STOCK_ISSUANCE'); // 'stockIssuance'
```
- Defined in src/utils/replicationHelpers.ts:152