fix: restore build script for release packaging (#19)

- Restore .trim() on models API JSON to prevent syntax error in
  generated models-snapshot.ts
- Fix archive path for scoped package names (@altimate/cli-*) in
  release tarball/zip creation
- Remove gh release upload from build.ts (handled by github-release job)
- Add CHANGELOG.md entry for v0.1.5

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: anandgupta42