feat(webui): show forked history boundary

webui/src/lib/nanobot-client.ts

@@ -352,6 +352,7 @@ export class NanobotClient {
   forkChat(
     sourceChatId: string,
     beforeUserIndex: number,
+    title?: string,
     timeoutMs: number = 5_000,
   ): Promise<string> {
     if (this.pendingNewChat) {
@@ -367,6 +368,7 @@ export class NanobotClient {
         type: "fork_chat",
         source_chat_id: sourceChatId,
         before_user_index: beforeUserIndex,
+        ...(title?.trim() ? { title: title.trim() } : {}),
       });
     });
   }

webui/src/lib/types.ts

@@ -862,6 +862,7 @@ export interface WebuiThreadPersistedPayload {
   sessionKey?: string;
   savedAt?: string;
   messages: UIMessage[];
+  fork_boundary_message_count?: number;
   workspace_scope?: WorkspaceScopePayload;
 }
 
@@ -877,7 +878,7 @@ export interface FilePreviewPayload {
 
 export type Outbound =
   | { type: "new_chat"; workspace_scope?: WorkspaceScopePayload }
-  | { type: "fork_chat"; source_chat_id: string; before_user_index: number }
+  | { type: "fork_chat"; source_chat_id: string; before_user_index: number; title?: string }
   | { type: "attach"; chat_id: string }
   | { type: "set_workspace_scope"; chat_id: string; workspace_scope: WorkspaceScopePayload }
   | { type: "transcribe_audio"; request_id: string; data_url: string; duration_ms?: number }