[REF] refactor file pool model and imports

- Refactor SnFilePool using freezed + sealed for consistency with other Sn models
- Add extension method listFromResponse for PoolService compatibility
- Update PoolService and utils to use SnFilePool
- Replace relative imports (../) with package imports for clarity and maintainability

Signed-off-by: Texas0295 <kimura@texas0295.top>

lib/screens/realm/realm_detail.g.dart

@@ -7,7 +7,7 @@ part of 'realm_detail.dart';
 // **************************************************************************
 
 String _$realmAppbarForegroundColorHash() =>
-    r'14b5563d861996ea182d0d2db7aa5c2bb3bbaf48';
+    r'8131c047a984318a4cc3fbb5daa5ef0ce44dfae5';
 
 /// Copied from Dart SDK
 class _SystemHash {