feat: add semantic-release for automated versioning and help dialog

- Set up semantic-release with zero-touch CI pipeline on push to main
- Add version sync script to keep all package.json files and APP_VERSION
  constant in sync automatically
- Consolidate Docker publishing into single tag-triggered workflow that
  pushes to both Docker Hub and ghcr.io with semver tags
- Add help dialog with keyboard shortcuts, getting started guide, and
  resource links
- Sync all versions to 0.2.1 to match Docker Hub latest

packages/ai/python/remove_bg.py

@@ -68,10 +68,8 @@ def main():
                 }
             )
         )
-        sys.exit(1)
     except Exception as e:
         print(json.dumps({"success": False, "error": str(e)}))
-        sys.exit(1)
 
 
 if __name__ == "__main__":