fix: make release checks portable on Windows

[xuhuanstudio]

Summary

• normalize generated-validator line endings before stale-content comparison
• run the generated-artifact check inside the required Windows CI job
• update serde_with to the patched 3.21.0 release
• advance the unpublished preview to Alpha 0.7 without moving the failed Alpha 0.6 tag

Validation

• full workspace lint, typecheck, tests, and production builds
• site link check and release-version synchronization
• Rust fmt, clippy, tests, and audit
• actionlint
• Windows release failure reproduced from GitHub job logs and covered by Windows CI