docs: make the documented install path executable

[rogerchappel]

Summary

• replace the unavailable npm-registry command with the project's current GitHub source install path
• build package output during Git dependency installation with prepare
• exercise an isolated consumer install and both packaged CLI aliases during every release check
• use npx --no-install in examples so commands never fall through to the registry

Commits

• 7ddfd8c test: verify source dependency installation
• 27b4d2e docs: use the current GitHub install path

Verification

• npm ci
• npm run release:check
• bash scripts/validate.sh
• git diff --check

All checks pass, including 17 tests and the new isolated source-install smoke check.