- Bump version to 1.9.0 in package.json, package-lock.json, .opencode/package.json
- Add v1.9.0 changelog with 212 commits covering selective install architecture,
6 new agents, 15+ new skills, session/state infrastructure, observer fixes,
12 language ecosystems, and community contributions
- Update README with v1.9.0 release notes and complete agents tree (27 agents)
- Add pytorch-build-resolver to AGENTS.md agent table
- Update documentation counts to 27 agents, 109 skills, 57 commands
- Update version references in zh-CN README
- All 1421 tests passing, catalog counts verified
