feat(localization): expand language support and enhance UI for user settings

- Added support for additional UI locales including Cebuano and Spanish, improving accessibility for a broader user base.
- Updated language selection components in the AppHeader and SettingsWidget to reflect new language options, enhancing user experience.
- Enhanced localization of various UI elements across components, ensuring consistent language representation and improved user engagement.
- Implemented logic to synchronize user language preferences with backend settings, providing a seamless experience when changing languages.

frontend/src/i18n/locales/en/home.json

@@ -1,5 +1,54 @@
 {
     "home": {
+        "dashboard": {
+            "kicker": "Your area",
+            "title": "Welcome back!",
+            "subtitle": "Your personal entry point to community, appointments, Falukant, and ongoing activity.",
+            "edit": "Edit dashboard",
+            "addWidget": "+ Add widget ...",
+            "addAgain": "Add again",
+            "done": "Done",
+            "sectionTitle": "Your overview",
+            "sectionIntro": "Widgets can be moved and adjusted in edit mode.",
+            "widgetTitlePlaceholder": "Title",
+            "removeWidget": "Remove widget",
+            "remove": "Remove",
+            "empty": "No widgets yet. Click “Edit dashboard” and then “+ Add widget”.",
+            "defaultAppointmentsWidget": "Appointments",
+            "loadError": "Dashboard could not be loaded.",
+            "saveError": "Dashboard could not be saved.",
+            "widgetLabels": {
+                "appointments": "Appointments",
+                "falukant": "Falukant",
+                "news": "News",
+                "birthdays": "Birthdays",
+                "upcoming": "Upcoming appointments",
+                "calendar": "Calendar"
+            },
+            "overview": {
+                "activeWidgetsLabel": "Active widgets",
+                "activeWidgetsText": "Your dashboard is modular and can be rearranged at any time.",
+                "availableModulesLabel": "Available modules",
+                "availableModulesText": "You can combine community, calendar, news, and Falukant modules.",
+                "editModeLabel": "Edit mode",
+                "editModeActive": "Active",
+                "editModeInactive": "Off",
+                "editModeActiveText": "Widgets can currently be added and adjusted.",
+                "editModeInactiveText": "Content stays focused and calm to read."
+            }
+        },
+        "vocabLanding": {
+            "eyebrow": "Learn languages online",
+            "title": "The vocabulary trainer on YourPart combines learning, courses, and practice in one platform.",
+            "lead": "Work with interactive lessons, grow your vocabulary, and use structured content for a motivating learning flow right in the browser.",
+            "cta": "Start for free",
+            "feature1Title": "Interactive courses",
+            "feature1Text": "Courses, lessons, and exercises help you build new language skills step by step.",
+            "feature2Title": "Practice-focused",
+            "feature2Text": "Vocabulary, grammar, and review are aligned with an everyday learning routine.",
+            "feature3Title": "Part of a community",
+            "feature3Text": "The language area is embedded in a larger community platform with blogs, forum, and chat."
+        },
         "betaNoticeLabel": "Beta notice:",
         "betaNoticeText": "YourPart is under active development. Features may be incomplete, information may still be missing and things can change.",
         "nologin": {