Fix Native Mode Sessions: implemented fork, revert, and sync for native sessions

packages/server/src/storage/session-store.ts

@@ -200,6 +200,54 @@ export class NativeSessionManager {
         return true
     }
 
+    async forkSession(workspaceId: string, sessionId: string): Promise<Session> {
+        const store = await this.loadStore(workspaceId)
+        const original = store.sessions[sessionId]
+        if (!original) throw new Error(`Session not found: ${sessionId}`)
+
+        const now = Date.now()
+        const forked: Session = {
+            ...original,
+            id: ulid(),
+            title: original.title ? `${original.title} (fork)` : "Forked Session",
+            parentId: original.parentId || original.id,
+            createdAt: now,
+            updatedAt: now,
+            messageIds: [...original.messageIds], // Shallow copy of message IDs
+        }
+
+        store.sessions[forked.id] = forked
+        await this.saveStore(workspaceId)
+        return forked
+    }
+
+    async revert(workspaceId: string, sessionId: string, messageId?: string): Promise<Session> {
+        const store = await this.loadStore(workspaceId)
+        const session = store.sessions[sessionId]
+        if (!session) throw new Error(`Session not found: ${sessionId}`)
+
+        if (!messageId) {
+            // Revert last message
+            if (session.messageIds.length > 0) {
+                const lastId = session.messageIds.pop()
+                if (lastId) delete store.messages[lastId]
+            }
+        } else {
+            // Revert to specific message
+            const index = session.messageIds.indexOf(messageId)
+            if (index !== -1) {
+                const toDelete = session.messageIds.splice(index + 1)
+                for (const id of toDelete) {
+                    delete store.messages[id]
+                }
+            }
+        }
+
+        session.updatedAt = Date.now()
+        await this.saveStore(workspaceId)
+        return session
+    }
+
     // Message operations
 
     async getSessionMessages(workspaceId: string, sessionId: string): Promise<SessionMessage[]> {