chore: prepare v1.9.0 release (#666)

- 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

CHANGELOG.md

@@ -1,5 +1,108 @@
 # Changelog
 
+## 1.9.0 - 2026-03-20
+
+### Highlights
+
+- Selective install architecture with manifest-driven pipeline and SQLite state store.
+- Language coverage expanded to 10+ ecosystems with 6 new agents and language-specific rules.
+- Observer reliability hardened with memory throttling, sandbox fixes, and 5-layer loop guard.
+- Self-improving skills foundation with skill evolution and session adapters.
+
+### New Agents
+
+- `typescript-reviewer` — TypeScript/JavaScript code review specialist (#647)
+- `pytorch-build-resolver` — PyTorch runtime, CUDA, and training error resolution (#549)
+- `java-build-resolver` — Maven/Gradle build error resolution (#538)
+- `java-reviewer` — Java and Spring Boot code review (#528)
+- `kotlin-reviewer` — Kotlin/Android/KMP code review (#309)
+- `kotlin-build-resolver` — Kotlin/Gradle build errors (#309)
+- `rust-reviewer` — Rust code review (#523)
+- `rust-build-resolver` — Rust build error resolution (#523)
+- `docs-lookup` — Documentation and API reference research (#529)
+
+### New Skills
+
+- `pytorch-patterns` — PyTorch deep learning workflows (#550)
+- `documentation-lookup` — API reference and library doc research (#529)
+- `bun-runtime` — Bun runtime patterns (#529)
+- `nextjs-turbopack` — Next.js Turbopack workflows (#529)
+- `mcp-server-patterns` — MCP server design patterns (#531)
+- `data-scraper-agent` — AI-powered public data collection (#503)
+- `team-builder` — Team composition skill (#501)
+- `ai-regression-testing` — AI regression test workflows (#433)
+- `claude-devfleet` — Multi-agent orchestration (#505)
+- `blueprint` — Multi-session construction planning
+- `everything-claude-code` — Self-referential ECC skill (#335)
+- `prompt-optimizer` — Prompt optimization skill (#418)
+- 8 Evos operational domain skills (#290)
+- 3 Laravel skills (#420)
+- VideoDB skills (#301)
+
+### New Commands
+
+- `/docs` — Documentation lookup (#530)
+- `/aside` — Side conversation (#407)
+- `/prompt-optimize` — Prompt optimization (#418)
+- `/resume-session`, `/save-session` — Session management
+- `learn-eval` improvements with checklist-based holistic verdict
+
+### New Rules
+
+- Java language rules (#645)
+- PHP rule pack (#389)
+- Perl language rules and skills (patterns, security, testing)
+- Kotlin/Android/KMP rules (#309)
+- C++ language support (#539)
+- Rust language support (#523)
+
+### Infrastructure
+
+- Selective install architecture with manifest resolution (`install-plan.js`, `install-apply.js`) (#509, #512)
+- SQLite state store with query CLI for tracking installed components (#510)
+- Session adapters for structured session recording (#511)
+- Skill evolution foundation for self-improving skills (#514)
+- Orchestration harness with deterministic scoring (#524)
+- Catalog count enforcement in CI (#525)
+- Install manifest validation for all 109 skills (#537)
+- PowerShell installer wrapper (#532)
+- Antigravity IDE support via `--target antigravity` flag (#332)
+- Codex CLI customization scripts (#336)
+
+### Bug Fixes
+
+- Resolved 19 CI test failures across 6 files (#519)
+- Fixed 8 test failures in install pipeline, orchestrator, and repair (#564)
+- Observer memory explosion with throttling, re-entrancy guard, and tail sampling (#536)
+- Observer sandbox access fix for Haiku invocation (#661)
+- Worktree project ID mismatch fix (#665)
+- Observer lazy-start logic (#508)
+- Observer 5-layer loop prevention guard (#399)
+- Hook portability and Windows .cmd support
+- Biome hook optimization — eliminated npx overhead (#359)
+- InsAIts security hook made opt-in (#370)
+- Windows spawnSync export fix (#431)
+- UTF-8 encoding fix for instinct CLI (#353)
+- Secret scrubbing in hooks (#348)
+
+### Translations
+
+- Korean (ko-KR) translation — README, agents, commands, skills, rules (#392)
+- Chinese (zh-CN) documentation sync (#428)
+
+### Credits
+
+- @ymdvsymd — observer sandbox and worktree fixes
+- @pythonstrup — biome hook optimization
+- @Nomadu27 — InsAIts security hook
+- @hahmee — Korean translation
+- @zdocapp — Chinese translation sync
+- @cookiee339 — Kotlin ecosystem
+- @pangerlkr — CI workflow fixes
+- @0xrohitgarg — VideoDB skills
+- @nocodemf — Evos operational skills
+- @swarnika-cmd — community contributions
+
 ## 1.8.0 - 2026-03-04
 
 ### Highlights