v0.9.0

What's Changed

• Variable oneof fixes by @rijesha in #318
• docs(tests): Tier A — testing docs overhaul + wire-format goldens by @Copilot in #319
• Tier B + C: sanitizer/matrix/fuzz/coverage CI and test scaffolding by @Copilot in #320
• Tier D: cross-language benchmarks, regression gate, dissector / API / doc-sample tests by @Copilot in #321
• Tier E: test stability policy, auto-generated coverage doc with triage, and CI badges by @Copilot in #322
• Fix Python decode validation + add golden decode direction + flip §7/§8 coverage to ✅ by @Copilot in #323
• Add test coverage for --equality, --validate, and caching; fix Rust PartialEq generation by @Copilot in #324
• Add wire-evolution interop scenarios 8–10 to all language runners by @Copilot in #325
• feat: Bump version to 0.9.0 [release] by @rijesha in #326

Full Changelog: v0.8.5...v0.9.0