defineErrors Related Skills : See for trySync/tryAsync usage and toast-on-error patterns. See for service architecture and namespace exports. When to Apply This Skill Use this pattern when you need to: - Define or refactor domain error variants using . - Add error variants that include structured fields and . - Centralize inside variant factories. - Infer union and single-variant types via / . - Replace old and split Err-pair patterns. Import Core Rules 1. All variants for a domain live in one call : never spread them across multiple calls 2. The factory function returns : that is the entire…