implement `lowdb` `factTriggers.findByConversationId`

database/lowdb.ts

@@ -121,6 +121,17 @@ const factTriggers: FactTriggerEntity = {
       (factTrigger) => factTrigger.id === id
     );
   },
+  findByConversationId: async (conversationId) => {
+    const messageIds = await dbClient.data.messages
+      .filter((m) => m.conversationId === conversationId)
+      .map((m) => m.id);
+    const factIds = dbClient.data.facts
+      .filter((fact) => messageIds.includes(fact.sourceMessageId))
+      .map((fact) => fact.id);
+    return dbClient.data.factTriggers.filter((factTrigger) =>
+      factIds.includes(factTrigger.sourceFactId)
+    );
+  },
   update: async (id, data: Partial<FactTrigger>) => {
     const factTriggerIndex = dbClient.data.factTriggers.findIndex(
       (factTrigger) => factTrigger.id === id