v0.9.0

What's Changed

• Add product PRDs and complete onboarding preview planning by @dblooman in #24
• Complete diagnostics and baseline drift milestone by @dblooman in #25
• Codex/prd1 2 docs by @dblooman in #26
• Fix lint findings, unused code, and dependency security checks by @dblooman in #27
• Prepare v0.9.0 release by @dblooman in #28

Full Changelog: v0.8.0...v0.9.0