feat: add Portuguese (PT-BR) translation (#132)

- Add pt.js translation file with complete PT-BR translations
- Add Portuguese option to language selector in settings
- Load pt.js translation file in index.html

Based on PR #108

Co-authored-by: Pedro Farias <feliperodriguesf62@gmail.com>
Co-authored-by: Wha1eChai <whaleora@gmail.com>

public/index.html

@@ -358,6 +358,7 @@
     <script src="js/translations/zh.js"></script>
     <script src="js/translations/tr.js"></script>
     <script src="js/translations/id.js"></script>
+    <script src="js/translations/pt.js"></script>
     <!-- 2. Alpine Stores (register alpine:init listeners) -->
     <script src="js/store.js"></script>
     <script src="js/data-store.js"></script>