chore(release): prepare 0.4.0

[hubab1]

What changed

• bump OpenASO from 0.3.2 (5) to 0.4.0 (6)
• remove the duplicate 0.3.1 changelog heading

Why

The release workflow rejects versions and build numbers that are not newer than the published Sparkle release. The product changes since 0.3.2 warrant a minor release.

Validation

• 624 tests across 54 suites passed on the release candidate source
• universal Release build succeeded for arm64 and x86_64
• Debug launch and MCP stdio process smoke tests passed
• bundled Node archives matched their pinned checksums
• public Sparkle feed comparison confirms 0.4.0 (6) is newer than 0.3.2 (5)
• git diff --check, plist, shell, and JavaScript validation passed