feat(webui): add tabbed pane workbench (#5322)

webui/src/lib/nanobot-client.ts

@@ -73,6 +73,7 @@ type SessionUpdateHandler = (
   scope?: SessionUpdateScope,
   workspaceScope?: WorkspaceScopePayload,
 ) => void;
+type SidebarStateUpdateHandler = (state: SidebarStatePayload) => void;
 type RunStatusHandler = (chatId: string, startedAt: number | null) => void;
 
 /** Structured errors surfaced to the UI.
@@ -178,6 +179,7 @@ export class NanobotClient {
   private statusHandlers = new Set<StatusHandler>();
   private runtimeModelHandlers = new Set<RuntimeModelHandler>();
   private sessionUpdateHandlers = new Set<SessionUpdateHandler>();
+  private sidebarStateUpdateHandlers = new Set<SidebarStateUpdateHandler>();
   private runStatusHandlers = new Set<RunStatusHandler>();
   private errorHandlers = new Set<ErrorHandler>();
   // chat_id -> handlers listening on it
@@ -275,6 +277,13 @@ export class NanobotClient {
     };
   }
 
+  onSidebarStateUpdate(handler: SidebarStateUpdateHandler): Unsubscribe {
+    this.sidebarStateUpdateHandlers.add(handler);
+    return () => {
+      this.sidebarStateUpdateHandlers.delete(handler);
+    };
+  }
+
   onRunStatus(handler: RunStatusHandler): Unsubscribe {
     this.runStatusHandlers.add(handler);
     for (const [chatId, startedAt] of this.runStartedAtByChatId) {
@@ -1149,6 +1158,11 @@ export class NanobotClient {
       return;
     }
 
+    if (parsed.event === "sidebar_state_updated") {
+      this.emitSidebarStateUpdate(parsed.state);
+      return;
+    }
+
     if (parsed.event === "error" && parsed.detail === "workspace_scope_rejected") {
       this.emitError({
         kind: "workspace_scope_rejected",
@@ -1198,6 +1212,12 @@ export class NanobotClient {
     }
   }
 
+  private emitSidebarStateUpdate(state: SidebarStatePayload): void {
+    for (const handler of this.sidebarStateUpdateHandlers) {
+      handler(state);
+    }
+  }
+
   private emitRunStatus(chatId: string, startedAt: number | null): void {
     for (const handler of this.runStatusHandlers) {
       handler(chatId, startedAt);