Release 0.9.0 - Changelog

• Added native support for SPZ v4 in both input and output.
• Kept SPZ v3 as the default write target to preserve backward compatibility.
• Extended SH handling up to degree 4, with correct inference, trimming, and roundtrip behavior.
• Added --preserve_sh4 as an experimental opt-in for compatible formats that can carry SH4.
• Updated format policies so standard exports remain capped at SH3 unless SH4 is explicitly preserved.
• Improved --info output to report SPZ versions, legacy vs standard SPZ files, and SH4 as an extended non-standard schema where applicable.
• Updated the format matrix and documentation to reflect native SPZ v4 support and the experimental SH4 preservation policy.