Improved lifecycle handling & code clean up (#1653)

## Description
Add some improvements related to life cycle handling whenever the app is
resumed:
- Refreshing the server-side user config 
- Refreshing the home page automatically

Also 401/403 errors accessing recording folders will be skipped since
this typically means the user lost access while the app was running.
Refreshing the server-side user config (above) will also help with this.

Finally, there's some general code clean up in `MainActivity` to move
non-UI related code out of Compose.

### Related issues
Closes #1647

### Testing
Emulator

## Screenshots
N/A

## AI or LLM usage
None

app/src/main/java/com/github/damontecres/wholphin/data/ServerRepository.kt

@@ -16,6 +16,7 @@ import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.withContext
 import kotlinx.serialization.Serializable
 import org.jellyfin.sdk.Jellyfin
@@ -298,6 +299,16 @@ class ServerRepository
                 response.content
             }
 
+        /**
+         * Update [currentUserDto] by querying the server
+         */
+        suspend fun updateUserDto() {
+            val userDto by apiClient.userApi.getCurrentUser()
+            _currentUserDto.update {
+                if (it?.id == userDto.id && currentUser?.id == userDto.id) userDto else it
+            }
+        }
+
         companion object {
             fun getServerSharedPreferences(context: Context): SharedPreferences =
                 context.getSharedPreferences(