Refacor electron app and add migrations

electron/cqrs/commands/handlers/saveReaction.ts

@@ -0,0 +1,26 @@
+import { DataSource } from 'typeorm';
+import { ReactionEntity } from '../../../entities';
+import { SaveReactionCommand } from '../../types';
+
+export async function handleSaveReaction(command: SaveReactionCommand, dataSource: DataSource): Promise<void> {
+  const repo = dataSource.getRepository(ReactionEntity);
+  const { reaction } = command.payload;
+  // Deduplicate: skip if same messageId + userId + emoji already exists
+  const existing = await repo.findOne({
+    where: { messageId: reaction.messageId, userId: reaction.userId, emoji: reaction.emoji }
+  });
+
+  if (existing)
+    return;
+
+  const entity = repo.create({
+    id: reaction.id,
+    messageId: reaction.messageId,
+    oderId: reaction.oderId ?? null,
+    userId: reaction.userId ?? null,
+    emoji: reaction.emoji,
+    timestamp: reaction.timestamp
+  });
+
+  await repo.save(entity);
+}