Refactor widget and worker to use UserPreferencesRepository

Refactored DayAheadWidget and WidgetUpdateWorker to use UserPreferencesRepository instead of accessing SharedPreferences directly.
This improves architectural consistency and centralizes data access logic.

Changes:
- Updated UserPreferencesRepository to expose summary flow and hasLocation method.
- Updated DayAheadWidget to inject UserPreferencesRepository and collect summary flow.
- Updated WidgetUpdateWorker to inject UserPreferencesRepository and use it for location check, preference retrieval, and summary saving.
- Addressed code review feedback: Added try-catch block in MainViewModel.fetchWeather.

Author: google-labs-jules[bot]

app/src/main/java/com/example/theloop/MainViewModel.kt

@@ -140,8 +140,12 @@ class MainViewModel @Inject constructor(
     }
 
     suspend fun fetchWeather(lat: Double, lon: Double) {
-         fetchLocationName(lat, lon)
-         weatherRepo.refresh(lat, lon, userPrefsRepo.tempUnit.first())
+        try {
+            fetchLocationName(lat, lon)
+            weatherRepo.refresh(lat, lon, userPrefsRepo.tempUnit.first())
+        } catch (e: Exception) {
+            android.util.Log.e("MainViewModel", "Error fetching weather or location name", e)
+        }
     }
 
     suspend fun fetchNews() {