getsentry/publish CommonJS Vitest conventions

Use getsentry/publish conventions: kebab-case source filenames, CommonJS require/module.exports, camelCase variables/functions, UPPER_SNAKE_CASE constants and regexes, and imports ordered Node built-ins, external packages, then local modules. Tests use Vitest globals and ES modules; mock external dependencies before importing the module under test because import-time dependency capture otherwise bypasses mocks. Use descriptive errors and early validation guards; throw on unexpected states rather than silently defaulting.