chore: bump version to 0.4.0 (#1937)

* chore: bump version to 0.4.0

* fix: restore newest-first ordering in CHANGELOG.md for v0.4.0 (#1938)

* Initial plan

* fix: move 0.4.0 section above 0.3.2 to restore newest-first ordering in CHANGELOG.md

Co-authored-by: mnriem <[email protected]>
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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: mnriem <[email protected]>

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Co-authored-by: Copilot <[email protected]>