feat(server): expose reuse latest chat (#12999)

fix AI-289

packages/backend/server/src/plugins/copilot/resolver.ts

@@ -64,6 +64,12 @@ class CreateChatSessionInput {
 
   @Field(() => Boolean, { nullable: true })
   pinned?: boolean;
+
+  @Field(() => Boolean, {
+    nullable: true,
+    description: 'true by default, compliant for old version',
+  })
+  reuseLatestChat?: boolean;
 }
 
 @InputType()

packages/backend/server/src/plugins/copilot/session.ts

@@ -446,7 +446,7 @@ export class ChatSessionService {
         // when client create chat session, we always find root session
         parentSessionId: null,
       },
-      true
+      options.reuseLatestChat ?? true
     );
   }
 

packages/backend/server/src/plugins/copilot/types.ts

@@ -76,6 +76,7 @@ export interface ChatSessionOptions {
   docId: string | null;
   promptName: string;
   pinned: boolean;
+  reuseLatestChat?: boolean;
 }
 
 export interface ChatSessionForkOptions

packages/backend/server/src/schema.gql

@@ -453,6 +453,9 @@ input CreateChatSessionInput {
 
   """The prompt name to use for the session"""
   promptName: String!
+
+  """true by default, compliant for old version"""
+  reuseLatestChat: Boolean
   workspaceId: String!
 }