setuptools 1.15.3a2 fixes event synchronization and bumps setuptools to 0.83.0

The setuptools project released version 1.15.3a2, addressing a synchronization issue with the kickoff-completed event and updating dependencies.

• Fixes synchronization of the kickoff-completed event with the OUTPUT hook result.
• Updates snapshot and changelog for v1.15.3a1.
• Bumps setuptools to 0.83.0 to address PYSEC-2026-3447.

Contributors to this release include @lucasgomide and @vinibrsl.