feat(vocab): add dashboard learning summary and related endpoints

- Introduced `getDashboardLearningSummary` method in `VocabService` to provide a compact overview of enrolled courses and current lessons for users.
- Updated `vocabController` to include a new route for the dashboard widget, allowing users to access their learning summary.
- Enhanced `vocabRouter` to route requests for the new dashboard widget endpoint.
- Added localization support for the new dashboard features across multiple languages, improving user engagement and accessibility.
- Updated UI components to integrate the new dashboard widget, ensuring a seamless user experience.

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

@@ -574,6 +574,20 @@
             "voteError": "Error while submitting the vote",
             "voteAllError": "Error while submitting the votes",
             "applyError": "Application could not be submitted.",
+            "benefits": {
+                "daily_salary": "Daily office stipend (once per day): about {amount}",
+                "tax_exemption": "Tax exemption: {regions}",
+                "tax_exemption_all": "Tax exemption: all regional levels",
+                "generic": "Benefit ({code})"
+            },
+            "regionLevels": {
+                "city": "City",
+                "county": "County",
+                "shire": "Shire",
+                "markgrave": "Margravate",
+                "duchy": "Duchy",
+                "country": "Country"
+            },
             "current": {
                 "office": "Office",
                 "region": "Region",