add support for publishing alpha branches to npm

[nikrom17]

Summary

Adds support for publishing alpha releases from non-main branches while keeping regular production releases on the main branch.

Changes

npm Scripts

• Added prebuild:release script to deduplicate build logic
• Added prerelease:alpha and postrelease:alpha lifecycle scripts for alpha releases
• Modified release:alpha to use standard-version --prerelease alpha

GitHub Actions Workflow

• Updated .github/workflows/publish.yml to detect current branch
• Main branch: publishes regular releases with latest tag
• Non-main branches: publishes alpha releases with alpha tag

How It Works

Regular Release (main branch):

# Trigger workflow from main branch
# Result: 5.8.0 → 5.9.0 (npm tag: latest)

Alpha Release (feature/dev branches):
# Trigger workflow from any other branch
# Result: 5.8.0 → 5.9.0-alpha.0 (npm tag: alpha)

Users can install alpha versions with:
npm install @krakenjs/beaver-logger@alpha

Benefits

- Safe testing of releases from feature branches
- Alpha releases don't affect production latest tag
- Single workflow handles both release types
- Automatic branch detection - no manual configuration needed