Retrieve a paginated list of sales with optional filters.

Filtering options:

• draft — include only draft (unvalidated) sales
• unpaid — include only sales with unpaid amounts
• paid — include only fully paid sales
• number — filter by sale number (alphanumeric)
• customer — filter by customer name or identifier (alphanumeric)
• search — general search term (alphanumeric)
• dateAfter — include sales on or after this date (format: YYYY-MM-DD)
• dateBefore — include sales on or before this date (format: YYYY-MM-DD)

Pagination:

• pageNumber — 1-based page number (default: 1)
• pageSize — results per page, max 100 (default: 10)