OData filter expression applied to breaks within the policy. Supported operators: eq (equals, use eq null to match NULL), ne (not equals, use ne null to match NOT NULL), lt (less than), le (less than or equal), gt (greater than), ge (greater than or equal), in (value in list), and (combine clauses). Not supported: or, not, parenthesized grouping. Filterable fields: id, name, paid, duration, availabilityType, availabilityMinHoursWorked, availabilityMaxHoursWorked, availabilityStartTime, availabilityEndTime, createdAt, updatedAt, deletedAt. Examples: name eq 'Lunch', paid eq true, paid eq false and name ne 'Quick Break'.