fix(release): honor Code 6 API boundary

[ZhiXiao-Lin]

Summary

• release the integrated MCP protocol expansion as 6.0.0 because it adds fields to public constructible Rust structs
• fix the nested TypeScript native-SDK test to construct platform-native paths on Windows
• run the SemVer comparison and Windows library suite on pull requests so release-only failures are caught before tagging
• retain the failed v5.3.6 tag as immutable history; no release artifacts were published from it

Validation

• scripts/check_release_versions.sh 6.0.0
• cargo fmt --all -- --check
• targeted nested native TypeScript SDK test after the standalone workspace setup
• bash scripts/check_semver.sh 5.3.5 (verified as a major change)
• git diff --check

The new PR checks provide the authoritative Windows and full CI evidence before merge.