Add stream language filter and fix directory infinite scroll.

Settings multi-select filters Top/category/tag lists via Helix (with over-fetch for multiple languages). Larger Helix pages, safer cursors, and scroll near-end loading restore pagination; GQL page-2 integrity failures end the list cleanly.

Co-authored-by: Cursor <cursoragent@cursor.com>

DESIGN.md

@@ -45,6 +45,16 @@ Helix cannot filter by freeform tags or sort ascending. GQL covers both:
 
 Key code: `lib/apis/twitch_gql_api.dart`, `lib/screens/home/search/`, `lib/widgets/stream_sort_button.dart`, `ListStore` / `ListType.tag`.
 
+## Stream languages (v5.2.4+)
+
+Settings → General → Stream languages (multi-select chips). Default `de`. Applied to Top, category, and tag lists.
+
+- One language: Helix `language=` (paginates cleanly, `first=100`)
+- Several languages: Helix over-fetch + client filter (still paginated)
+- Tags / ascending sort: GQL with `languages: [Language!]`; page-2 often hits Twitch integrity — treated as end-of-list after the first page of 30
+
+Also fixed infinite scroll: larger Helix pages, defensive cursors, scroll near-end load-more, and stop disposing shared Home scroll controllers.
+
 ## Build
 
 Flutter **3.47.0** (pinned in `pubspec.yaml`). Local SDK: `/home/yuna/.local/flutter-3.47.0`.