feat(mobile): keep search results visible (#26498)

Search results are replaced with a spinner when loading the next page,
which is quite jarring. Search results now remain visible when loading
the next page with a spinner at the bottom. The next page also loads
sooner, which makes it feel a lot smoother.

Co-authored-by: Alex <alex.tran1502@gmail.com>

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

@@ -276,6 +276,19 @@ class DriftTimelineRepository extends DriftDatabaseRepository {
     origin: origin,
   );
 
+  TimelineQuery fromAssetStream(List<BaseAsset> Function() getAssets, Stream<int> assetCount, TimelineOrigin origin) =>
+      (
+        bucketSource: () async* {
+          yield _generateBuckets(getAssets().length);
+          yield* assetCount.map(_generateBuckets);
+        },
+        assetSource: (offset, count) {
+          final assets = getAssets();
+          return Future.value(assets.skip(offset).take(count).toList(growable: false));
+        },
+        origin: origin,
+      );
+
   TimelineQuery fromAssetsWithBuckets(List<BaseAsset> assets, TimelineOrigin origin) {
     // Sort assets by date descending and group by day
     final sorted = List<BaseAsset>.from(assets)..sort((a, b) => b.createdAt.compareTo(a.createdAt));