feat: add historical data

lib/services/remote_sync_service.dart

@@ -1,4 +1,5 @@
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
 
 import 'package:drift/drift.dart';
@@ -45,6 +46,9 @@ class RemoteSyncService {
   static const _venueIdKey = 'remote_venue_id';
   static const _syncStateId = 'default';
 
+  /// Most outbox events sent per sync; a larger backlog drains over syncs.
+  static const maxEventsPerSync = 500;
+
   static const _pollingInterval = Duration(
     seconds: kSyncPollingIntervalSeconds,
   );
@@ -227,6 +231,8 @@ class RemoteSyncService {
 
   Future<void> _doSync(_Credentials credentials) async {
     final state = await _getSyncState();
+    // Read before the snapshot, so the snapshot is never older than the events
+    final outbox = await _pendingEvents();
     final openTabs = await barTabService.getOpenTabs();
 
     final response = await apiClient.sync(
@@ -235,9 +241,15 @@ class RemoteSyncService {
         deviceId: credentials.deviceId,
         cursor: state?.serverCursor,
         openTabs: openTabs.map(_toSnapshot).toList(),
+        events: [
+          for (final row in outbox)
+            jsonDecode(row.payload) as Map<String, dynamic>,
+        ],
       ),
     );
 
+    await _clearSentEvents(response);
+
     for (final command in response.commands) {
       await _processCommand(command, credentials);
     }
@@ -251,6 +263,38 @@ class RemoteSyncService {
     await _updateSyncState(success: true, cursor: response.cursor);
   }
 
+  Future<List<TabEventRow>> _pendingEvents() {
+    return (database.select(database.tabEvents)
+          ..orderBy([
+            (row) => OrderingTerm.asc(row.createdAt),
+            // Same-second events keep their insertion order
+            (row) => OrderingTerm.asc(const CustomExpression<int>('rowid')),
+          ])
+          ..limit(maxEventsPerSync))
+        .get();
+  }
+
+  /// Events the server stored or refused leave the outbox. Events created
+  /// while the sync was in flight are in neither list and go next time.
+  Future<void> _clearSentEvents(SyncResponse response) async {
+    for (final rejected in response.rejectedEvents) {
+      debugPrint(
+        'RemoteSyncService: event ${rejected.id} rejected: ${rejected.reason}',
+      );
+    }
+
+    final ids = {
+      ...response.acknowledgedEventIds,
+      for (final rejected in response.rejectedEvents)
+        if (rejected.id != null) rejected.id!,
+    };
+    if (ids.isEmpty) return;
+
+    await (database.delete(
+      database.tabEvents,
+    )..where((row) => row.id.isIn(ids))).go();
+  }
+
   SnapshotTab _toSnapshot(BarTab tab) {
     return SnapshotTab(
       id: tab.id,
@@ -309,6 +353,7 @@ class RemoteSyncService {
         command.tabId,
         paymentMethod: PaymentMethod.fromValue(command.paymentMethod),
         expectedVersion: command.expectedVersion,
+        commandId: command.id,
       );
 
       _eventController.add(