Add npm create adoption flow

[theinfosecguy]

Summary

• Add interactive CLI mode when servergen is run without an app name in a TTY
• Add the create-servergen wrapper package for npm create servergen@latest
• Prepare the 2.3.0 release notes, README quick start, examples docs, and two-package release workflow

Tests

• npm test
• npm run test:package
• npm pack --dry-run
• npm pack --dry-run in packages/create-servergen

Release note

create-servergen is a new npm package name. The first publish may require npm owner bootstrap/manual publish or token-based publish before trusted publishing can be configured for future tag releases.