v0.4.1

Patch release after the public npm launch.

Changes:

• Add command-specific help for join/frame/doctor.
• Add samoagent doctor for local prerequisite checks.
• Include docs/release-checklist.md in the repo and package.
• Keep CI/publish workflows ready for GitHub Actions Node 24.

Validation:

• bun test
• bun run build
• npm pack --dry-run
• GitHub CI green