Tuple syntax in whereIn() fails with NULL values (regression in 2.5.0)

[WMOH-DEV]

Version 2.5.0 changed the whereIn() implementation for composite keys from
using OR/WHERE clauses to tuple syntax. This breaks queries when NULL values
are involved because SQL tuple comparisons don't handle NULL correctly.

Example:

• New (2.5.x): (col1, col2, col3) IN ((1, 2, NULL)) → returns 0 rows (broken)
• Old (2.4.x): col1 = 1 AND col2 = 2 AND col3 IS NULL → returns correct rows (works)

Affected: All composite key relationships with nullable columns