test(flutter): re-enable drift tests after ci-flutter:1.26 ships libsqlite3-0

Drops the libsqlite3-missing skip cohort now that the ci-flutter
runner image installs libsqlite3-0 (CI-runner commit on its main).

Per-file removals (no behavior change in tests themselves — they
just stop being skipped):
- `@Tags(['drift'])` + `library;` directive from 5 files.
- `const _skipDrift = ...;` declaration + its rationale comment
  from 6 files (the 5 above + like_button_test.dart, which had its
  own _skipDrift for the rollback-via-drift case).
- `skip: _skipDrift` annotations from 17 test invocations across
  those 6 files (16 single-line + 1 multi-line in like_button).
- Stale `@Tags(['drift']) tier covers it` reference in
  home_screen_test.dart's drift-coverage comment.

Net -79 +18 lines across 7 files; 17 previously-silent tests are
now part of the CI signal. Fable #399.

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

flutter_client/test/quarantine/quarantine_provider_test.dart

@@ -1,6 +1,3 @@
-@Tags(['drift'])
-library;
-
 import 'package:drift/native.dart' show NativeDatabase;
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_test/flutter_test.dart';
@@ -11,13 +8,6 @@ import 'package:minstrel/cache/db.dart';
 import 'package:minstrel/models/track.dart';
 import 'package:minstrel/quarantine/quarantine_provider.dart';
 
-// SKIP NOTE: drift's NativeDatabase needs the system libsqlite3.so.
-// The flutter-ci runner image doesn't ship it. Same skip as
-// sync_controller_test.dart — unblock by adding libsqlite3-dev to the
-// CI image, or switch to sqlite3/wasm. On-device runs cover real
-// behaviour today.
-const _skipDrift = 'libsqlite3 missing on flutter-ci runner; on-device covers';
-
 class _StubQuarantineApi implements QuarantineApi {
   _StubQuarantineApi({this.shouldThrow = false});
   bool shouldThrow;
@@ -72,7 +62,7 @@ Future<void> _seed(AppDb db) async {
 }
 
 void main() {
-  test('flag inserts a drift row and calls the server', skip: _skipDrift,
+  test('flag inserts a drift row and calls the server',
       () async {
     final db = AppDb(NativeDatabase.memory());
     addTearDown(db.close);
@@ -92,8 +82,7 @@ void main() {
     expect(rows.first.reason, 'bad_rip');
   });
 
-  test('flag keeps drift optimistic + queues mutation on server failure',
-      skip: _skipDrift, () async {
+  test('flag keeps drift optimistic + queues mutation on server failure', () async {
     final db = AppDb(NativeDatabase.memory());
     addTearDown(db.close);
     final api = _StubQuarantineApi(shouldThrow: true);
@@ -115,7 +104,7 @@ void main() {
     expect(mutations.first.kind, 'quarantine.flag');
   });
 
-  test('unflag deletes the drift row and calls the server', skip: _skipDrift,
+  test('unflag deletes the drift row and calls the server',
       () async {
     final db = AppDb(NativeDatabase.memory());
     addTearDown(db.close);
@@ -132,7 +121,7 @@ void main() {
     expect(rows, isEmpty);
   });
 
-  test('isHidden reflects drift state', skip: _skipDrift, () async {
+  test('isHidden reflects drift state', () async {
     final db = AppDb(NativeDatabase.memory());
     addTearDown(db.close);
     await _seed(db);