refactor: hashing service (#21997)

* download only backup selected assets

* android impl

* fix tests

* limit concurrent hashing to 16

* extension cleanup

* optimized hashing

* hash only selected albums

* remove concurrency limit

* address review comments

* log more info on failure

* add native cancellation

* small batch size on ios, large on android

* fix: get correct resources

* cleanup getResource

* ios better hash cancellation

* handle graceful cancellation android

* do not trigger multiple hashing ops

* ios: fix circular reference, improve cancellation

* kotlin: more cancellation checks

* no need to create result

* cancel previous task

* avoid race condition

* ensure cancellation gets called

* fix cancellation not happening

---------

Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com>
Co-authored-by: mertalev <101130780+mertalev@users.noreply.github.com>
Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/lib/infrastructure/repositories/local_asset.repository.dart

@@ -36,17 +36,17 @@ class DriftLocalAssetRepository extends DriftDatabaseRepository {
 
   Stream<LocalAsset?> watch(String id) => _assetSelectable(id).watchSingleOrNull();
 
-  Future<void> updateHashes(Iterable<LocalAsset> hashes) {
+  Future<void> updateHashes(Map<String, String> hashes) {
     if (hashes.isEmpty) {
       return Future.value();
     }
 
     return _db.batch((batch) async {
-      for (final asset in hashes) {
+      for (final entry in hashes.entries) {
         batch.update(
           _db.localAssetEntity,
-          LocalAssetEntityCompanion(checksum: Value(asset.checksum)),
-          where: (e) => e.id.equals(asset.id),
+          LocalAssetEntityCompanion(checksum: Value(entry.value)),
+          where: (e) => e.id.equals(entry.key),
         );
       }
     });