feat: recent searches history in SearchScreen (U3) (#47)

lib/data/db/database.dart

@@ -234,6 +234,13 @@ class Drafts extends Table {
   TextColumn get imapServerId => text().nullable()();
 }
 
+@DataClassName('SearchHistoryRow')
+class SearchHistoryEntries extends Table {
+  IntColumn get id => integer().autoIncrement()();
+  TextColumn get query => text()();
+  DateTimeColumn get searchedAt => dateTime()();
+}
+
 @DataClassName('UndoActionRow')
 class UndoActions extends Table {
   TextColumn get id => text()();
@@ -263,13 +270,14 @@ class UndoActions extends Table {
     SyncLogMailboxes,
     SyncHealth,
     UndoActions,
+    SearchHistoryEntries,
   ],
 )
 class AppDatabase extends _$AppDatabase {
   AppDatabase([QueryExecutor? executor]) : super(executor ?? _openConnection());
 
   @override
-  int get schemaVersion => 26;
+  int get schemaVersion => 27;
 
   Future<void> _createEmailFts() async {
     await customStatement('''
@@ -492,6 +500,9 @@ class AppDatabase extends _$AppDatabase {
               SELECT rowid, subject, preview, from_json FROM emails
             ''');
           }
+          if (from < 27) {
+            await m.createTable(searchHistoryEntries);
+          }
         },
       );
 }

lib/data/repositories/search_history_repository_impl.dart

@@ -0,0 +1,57 @@
+import 'package:drift/drift.dart';
+import 'package:sharedinbox/core/repositories/search_history_repository.dart';
+import 'package:sharedinbox/data/db/database.dart';
+
+class SearchHistoryRepositoryImpl implements SearchHistoryRepository {
+  SearchHistoryRepositoryImpl(this._db);
+  final AppDatabase _db;
+
+  static const _maxEntries = 10;
+
+  @override
+  Future<List<String>> getRecentSearches() async {
+    final rows = await (_db.select(_db.searchHistoryEntries)
+          ..orderBy([(t) => OrderingTerm.desc(t.searchedAt)])
+          ..limit(_maxEntries))
+        .get();
+    return rows.map((r) => r.query).toList();
+  }
+
+  @override
+  Future<void> saveSearch(String query) async {
+    final trimmed = query.trim();
+    if (trimmed.isEmpty) return;
+
+    await _db.transaction(() async {
+      // Remove existing entry for same query (deduplication).
+      await (_db.delete(_db.searchHistoryEntries)
+            ..where((t) => t.query.equals(trimmed)))
+          .go();
+
+      await _db.into(_db.searchHistoryEntries).insert(
+            SearchHistoryEntriesCompanion.insert(
+              query: trimmed,
+              searchedAt: DateTime.now(),
+            ),
+          );
+
+      // Prune to the most recent _maxEntries.
+      final keepIds = await (_db.select(_db.searchHistoryEntries)
+            ..orderBy([(t) => OrderingTerm.desc(t.searchedAt)])
+            ..limit(_maxEntries))
+          .map((r) => r.id)
+          .get();
+
+      if (keepIds.isNotEmpty) {
+        await (_db.delete(_db.searchHistoryEntries)
+              ..where((t) => t.id.isNotIn(keepIds)))
+            .go();
+      }
+    });
+  }
+
+  @override
+  Future<void> clearHistory() async {
+    await _db.delete(_db.searchHistoryEntries).go();
+  }
+}