docs(agents): fix dart-define names, default to tests, drop lint-enforced style rules

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -6,10 +6,8 @@
 
 ## Code Opinions
 
-- Package imports (`import 'package:frosty/...'`), not relative imports
-- Trailing commas always
-- Single quotes
 - Extract related/grouped logic (state, reactions, actions) into dedicated stores when it improves readability — keep widgets focused on rendering
+- Default to writing tests: new or changed logic (stores, API clients, parsing, utils) ships with tests; when touching existing tested code, update or extend its tests. Pure UI/rendering or config changes may skip.
 
 ## Infrastructure Checklist
 
@@ -29,9 +27,9 @@ Flutter mobile app for browsing Twitch on iOS and Android. Uses MobX for state m
 
 ```bash
 flutter pub get                                                     # Install dependencies
-flutter run --dart-define=clientId=ID --dart-define=secret=SECRET   # Run with Twitch credentials
+flutter run --dart-define=CLIENT_ID=ID --dart-define=SECRET=SECRET  # Run with Twitch credentials
 flutter analyze                                                     # Static analysis (run after changes)
-flutter test                                                        # Run tests (if changes touch testable logic)
+flutter test                                                        # Run tests
 dart run build_runner build                                         # Regenerate .g.dart files (MobX/JSON models)
 dart run build_runner build --delete-conflicting-outputs             # Same, but clears stale outputs
 ```