chore: prepare 0.1.0-alpha.9 release

[chasechou007]

Summary

• bump package and lockfile to 0.1.0-alpha.9
• freeze the Agent-driven installation work under a dated alpha.9 changelog section
• keep Homebrew deferred and npm latest unchanged

Local release gates

• 178 tests passed on Node.js 20.20.2, 22.23.2, and 24.18.0
• exact alpha.9 installed-package and global Agent bootstrap smokes passed
• npm dry-run: 60 public files, INSTALL.md included, private/process and maintainer-only files excluded
• npm audit: 0 vulnerabilities
• OpenDomain: 26 documents passed with the existing stale candidate-0002 warning
• OpenSpec: 11/11 items passed in the private nested repository
• macOS arm64 standalone build, Agent smoke, codesign, architecture, and version checks passed
• npm publication identity verified as chasechou007

Publication boundary

Publication starts only after this PR passes CI and four-platform standalone verification, is squash-merged, and the merged main source is rechecked.