feat: add French and Spanish translations (#77)

- Complete fr.json (1049 keys, 52 sections)
- Complete es.json (1049 keys, 52 sections)
- Language selector updated with Francais and Espanol
- Setup wizard localized for fr/es
- Default fallback language changed from 'it' to 'en'
- Version bump to 1.7.17

README.md

@@ -24,8 +24,8 @@
 [![PHP](https://img.shields.io/badge/PHP-8.0+-blue.svg)](https://www.php.net/)
 [![SQLite](https://img.shields.io/badge/SQLite-3-blue.svg)](https://www.sqlite.org/)
 [![Docker](https://img.shields.io/badge/Docker-Ready-2496ED.svg)](Dockerfile)
-[![i18n](https://img.shields.io/badge/i18n-IT%20%7C%20EN%20%7C%20DE-orange.svg)](translations/)
-[![Version](https://img.shields.io/badge/version-1.7.15-brightgreen.svg)](CHANGELOG.md)
+[![i18n](https://img.shields.io/badge/i18n-IT%20%7C%20EN%20%7C%20DE%20%7C%20FR%20%7C%20ES-orange.svg)](translations/)
+[![Version](https://img.shields.io/badge/version-1.7.17-brightgreen.svg)](CHANGELOG.md)
 [![GitHub stars](https://img.shields.io/github/stars/dadaloop82/EverShelf?style=social)](https://github.com/dadaloop82/EverShelf/stargazers)
 [![Last commit](https://img.shields.io/github/last-commit/dadaloop82/EverShelf/main)](https://github.com/dadaloop82/EverShelf/commits/main)
 [![Contributors](https://img.shields.io/github/contributors/dadaloop82/EverShelf)](https://github.com/dadaloop82/EverShelf/graphs/contributors)
@@ -365,6 +365,8 @@ The app supports multiple languages via JSON translation files in the `translati
 | 🇮🇹 Italian (it) | ✅ Complete (base) |
 | 🇬🇧 English (en) | ✅ Complete |
 | 🇩🇪 German (de) | ✅ Complete |
+| 🇫🇷 French (fr) | ✅ Complete |
+| 🇪🇸 Spanish (es) | ✅ Complete |
 
 **Want to add your language?** See the [Translation Guide](CONTRIBUTING.md#-adding-translations) — just copy `translations/it.json`, translate the values, and submit a PR!