3.31.5

• Fixed OSError: [Errno 22] Invalid argument when reading native Datetime64 value before 1970 (negative Unix timestamps) on Windows: conversion now uses epoch arithmetic instead of datetime.utcfromtimestamp
• Add return_not_null_data_as_optional parameter to read_table (sync and async) — allows reading NOT NULL columns as non-optional types, matching the existing gRPC field and the C++ SDK's ReturnNotNullAsOptional. By default read_table still wraps NOT NULL columns in Optional for backward compatibility

Full Changelog: 3.31.4...3.31.5