feat(platform_playlist): CV-017 -- persistent canonical channel identity (Drift/SQLite)

packages/platform_playlist/lib/platform_playlist.dart

@@ -15,6 +15,8 @@ export 'src/smart_playlist_evaluator.dart';
 export 'src/channel_name_normalizer.dart';
 export 'src/canonical_channel_matcher.dart';
 export 'src/favorite_channel_remapper.dart';
+export 'src/persistence/canonical_channel_database.dart';
+export 'src/persistence/canonical_channel_repository.dart';
 export 'src/xtream/xtream_client.dart';
 export 'src/xtream/xtream_content_source.dart';
 export 'src/xtream/xtream_epg_repository.dart';

packages/platform_playlist/lib/src/persistence/canonical_channel_database.dart

@@ -0,0 +1,78 @@
+import 'dart:io';
+
+import 'package:drift/drift.dart';
+import 'package:drift/native.dart';
+import 'package:path/path.dart' as p;
+import 'package:path_provider/path_provider.dart';
+
+part 'canonical_channel_database.g.dart';
+
+/// Canonical channel identities (CV-017): a normalized, user-facing channel
+/// concept that provider aliases point to when confidently matched.
+class CanonicalChannels extends Table {
+  TextColumn get canonicalChannelId => text()();
+  TextColumn get displayName => text()();
+  TextColumn get normalizedName => text()();
+  TextColumn get language => text().nullable()();
+  TextColumn get country => text().nullable()();
+  TextColumn get category => text().nullable()();
+  TextColumn get logoFingerprint => text().nullable()();
+  DateTimeColumn get createdAt => dateTime()();
+  DateTimeColumn get updatedAt => dateTime()();
+
+  @override
+  Set<Column> get primaryKey => {canonicalChannelId};
+}
+
+/// A single provider's channel entry, optionally pointing at a canonical
+/// identity once matched with sufficient confidence (CV-017). Kept separate
+/// from [CanonicalChannels] per the issue's "store provider channel aliases
+/// separately from user-facing canonical identities" framework rule.
+@DataClassName('ProviderChannelAlias')
+class ProviderChannelAliases extends Table {
+  TextColumn get sourceId => text()();
+  TextColumn get providerChannelId => text()();
+  TextColumn get canonicalChannelId => text().nullable()();
+  TextColumn get providerName => text()();
+  TextColumn get normalizedProviderName => text()();
+  IntColumn get tvgId => integer().nullable()();
+  TextColumn get groupTitle => text().nullable()();
+  TextColumn get streamUrlFingerprint => text()();
+  TextColumn get resolution => text().nullable()();
+  BoolColumn get isVod => boolean().withDefault(const Constant(false))();
+  BoolColumn get isRadio => boolean().withDefault(const Constant(false))();
+  BoolColumn get isAdult => boolean().withDefault(const Constant(false))();
+  // Stored as the ChannelMatchConfidence enum's name ('high'/'medium'/
+  // 'low'/'none'), not a raw double -- keeps the persisted value tied to
+  // CanonicalChannelMatcher's actual confidence tiers instead of an
+  // arbitrary score that could drift out of sync with matcher logic.
+  TextColumn get matchConfidence => text().nullable()();
+
+  @override
+  Set<Column> get primaryKey => {sourceId, providerChannelId};
+}
+
+@DriftDatabase(tables: [CanonicalChannels, ProviderChannelAliases])
+class CanonicalChannelDatabase extends _$CanonicalChannelDatabase {
+  CanonicalChannelDatabase(super.executor);
+
+  /// Opens the real on-device database file. Not used in tests -- see
+  /// [CanonicalChannelDatabase.forTesting] for an in-memory instance.
+  factory CanonicalChannelDatabase.open() {
+    return CanonicalChannelDatabase(
+      LazyDatabase(() async {
+        final dir = await getApplicationSupportDirectory();
+        final file = File(p.join(dir.path, 'canonical_channels.sqlite'));
+        return NativeDatabase.createInBackground(file);
+      }),
+    );
+  }
+
+  /// An in-memory database for tests -- never touches disk.
+  factory CanonicalChannelDatabase.forTesting() {
+    return CanonicalChannelDatabase(NativeDatabase.memory());
+  }
+
+  @override
+  int get schemaVersion => 1;
+}