fix(flutter): analyze errors after Plan C provider migrations

- cache_first.dart: backtick-fence List<T> doc comment to dodge
  unintended_html_in_doc_comment.
- library_providers.dart:163: switch single-row insert to
  insertAllOnConflictUpdate; Batch only exposes the *AllOnConflict*
  variant.
- 5 test files: StreamProvider.overrideWith takes Create<Stream<T>>,
  not Create<Future<T>>. Wrap data emissions in Stream.value(...).
- artist_detail_screen_test: add models/album.dart import for AlbumRef
  type annotation.
- track_actions_sheet_test: drop _StubLiked extends LikedIdsController
  (notifier no longer exists post-migration); override with
  Stream.value(LikedIds(...)) instead.
- like_button_test: rollback assertion now requires drift writes via
  LikesController. Skip under _skipDrift until libsqlite3-dev lands on
  the runner image (Fable #399). Replace stale .notifier reference
  with likesControllerProvider for completeness.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

flutter_client/test/library/home_screen_test.dart

@@ -28,7 +28,7 @@ void main() {
       overrides: [
         homeProvider.overrideWith((ref) async => _emptyHome),
         playlistsListProvider('all').overrideWith(
-          (ref) async => PlaylistsList.empty(),
+          (ref) => Stream.value(PlaylistsList.empty()),
         ),
         systemPlaylistsStatusProvider.overrideWith(
           (ref) async => SystemPlaylistsStatus.empty(),
@@ -48,7 +48,7 @@ void main() {
       overrides: [
         homeProvider.overrideWith((ref) async => _emptyHome),
         playlistsListProvider('all').overrideWith(
-          (ref) async => PlaylistsList.empty(),
+          (ref) => Stream.value(PlaylistsList.empty()),
         ),
         systemPlaylistsStatusProvider.overrideWith(
           (ref) async => SystemPlaylistsStatus.empty(),
@@ -89,8 +89,8 @@ void main() {
       overrides: [
         homeProvider.overrideWith((ref) async => _emptyHome),
         playlistsListProvider('all').overrideWith(
-          (ref) async =>
-              const PlaylistsList(owned: [forYou], public: []),
+          (ref) => Stream.value(
+              const PlaylistsList(owned: [forYou], public: [])),
         ),
         systemPlaylistsStatusProvider.overrideWith(
           (ref) async => SystemPlaylistsStatus.empty(),
@@ -120,7 +120,7 @@ void main() {
       overrides: [
         homeProvider.overrideWith((ref) async => home),
         playlistsListProvider('all').overrideWith(
-          (ref) async => PlaylistsList.empty(),
+          (ref) => Stream.value(PlaylistsList.empty()),
         ),
         systemPlaylistsStatusProvider.overrideWith(
           (ref) async => SystemPlaylistsStatus.empty(),