* feat: add decimal support to currency system with ISO 4217 data integration
* Harden currency formatting: add decimal bounds, input validation, and robust error handling
* Fixed issues raised by coderrabitai
* Fixed linting issue
Retries + logging: Set timestamped errors on 5xx/429 or JSON failures.
Empty-array guard: script exits non-zero if the API returns [], so won’t commit an empty file.
Exit codes: any API or I/O error yields sys.exit(1), triggering “no commit on failure” logic.
