[xudong963]

Which issue does this PR close?

• Part of Release DataFusion 56.0.0 (Oct/Nov 2026) #24461

Rationale for this change

branch-56 has been created from main for the 56.x.y release series, so new changes on main will ship in 57.0.0. Per the release process, bump main to the next development version so that:

• builds from main are distinguishable from branch-56 builds
• the release version labeler tags newly merged PRs with v57.0.0 rather than v56.0.0

What changes are included in this PR?

Generated by following the release guide:

python3 dev/update_datafusion_versions.py 57.0.0-dev
cargo update --workspace
./ci/scripts/doc_prettier_check.sh --write --allow-dirty

• Bump the workspace version and datafusion-* dependency versions in Cargo.toml / Cargo.lock to 57.0.0-dev
• Regenerate docs/source/user-guide/configs.md (the default datafusion.execution.parquet.created_by embeds the version)
• Update target_version in ci/scripts/release_version_labeler.js to v57.0.0

User-facing crate examples (e.g. docs/source/download.md) intentionally keep pointing at the latest released version.

What is the testing strategy for this PR?

Existing CI.

Are there any user-facing changes?

Builds from main now report version 57.0.0-dev instead of 56.0.0-dev.

[kosiew]

@xudong963
LGTM

[alamb]

🚀