Add freeform tag search and viewer sort for live lists.

Helix cannot filter by tags or sort ascending; use Twitch GQL for Search→Tags→streams and Most/Fewest viewers on Top, category, and tag screens.

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

DESIGN.md

@@ -36,6 +36,15 @@ Browser vaft hooks `Worker`/`fetch` and rewrites m3u8. Frosty’s native player
 - Third-party proxies
 - HLS segment stripping inside `better_native_video_player` (unless smoke tests demand it)
 
+## Tags + viewer sort (v5.2.2+)
+
+Helix cannot filter by freeform tags or sort ascending. GQL covers both:
+
+- Search: `SearchFreeformTags` → tap → `TagStreams` (`streams` + `freeformTags`)
+- Sort: Top (asc), category (`game.streams`), tag — `VIEWER_COUNT` / `VIEWER_COUNT_ASC` via `StreamSortButton`
+
+Key code: `lib/apis/twitch_gql_api.dart`, `lib/screens/home/search/`, `lib/widgets/stream_sort_button.dart`, `ListStore` / `ListType.tag`.
+
 ## Build
 
 Flutter **3.47.0** (pinned in `pubspec.yaml`). Local SDK: `/home/yuna/.local/flutter-3.47.0`.