Release v0.57.0

What's Changed

• fix(client): make initialized state atomic by @MitulShah1 in #936
• fix(mcp): support jsonschema_description and enum struct tags by @syf2211 in #931
• fix(streamable_http): close active sessions before Shutdown by @syf2211 in #926
• fix(client): accept Content-Type parameters on GET listening stream by @Yusufihsangorgel in #925
• fix(server): label client JSON-RPC errors by method in streamable HTTP by @zent7x in #924
• fix(mcp): unmarshal embedded resource contents by @jstar0 in #938
• feat(server): add streamable HTTP stream resumability via pluggable EventStore by @Abhinav2408 in #930
• docs(examples): fix stale struct tags in structured I/O example by @zent7x in #923
• fix(transport): concatenate multi-line SSE data fields instead of overwriting by @Yusufihsangorgel in #927
• fix: deliver server notifications to in-process transport clients by @jgangemi in #919

New Contributors

• @MitulShah1 made their first contribution in #936
• @Yusufihsangorgel made their first contribution in #925
• @zent7x made their first contribution in #924
• @jgangemi made their first contribution in #919

Full Changelog: v0.56.0...v0.57.0