Fix missing translation keys for Bible reader settings dialog

- Add theme button translations: light, dark, sepia
- Add close button translation for settings dialog
- Complete internationalization for Romanian and English locales

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

messages/en.json

@@ -134,7 +134,11 @@
       "removeBookmark": "Remove bookmark",
       "bookmarkVerse": "Bookmark verse",
       "removeVerseBookmark": "Remove verse bookmark",
-      "toggleFullscreen": "Toggle fullscreen"
+      "toggleFullscreen": "Toggle fullscreen",
+      "light": "Light",
+      "dark": "Dark",
+      "sepia": "Sepia",
+      "close": "Close"
     },
     "prayers": {
       "title": "Prayers",