feat(react-core): forward followUp option through useComponent (CopilotKit#4897)

## Summary

`useComponent` wraps `useFrontendTool` but wasn't forwarding `followUp`.
Adds the option to the config and passes it through.

## Changes

- Forward `followUp?: boolean` from `useComponent` config to
`useFrontendTool`
- Add test coverage in `use-component.test.tsx` (`forwards followUp
option to useFrontendTool`)
- Document the option in the v2 hook reference

## Test plan

- [x] `nx test react-core` passes (new `forwards followUp option to
useFrontendTool` case)
- [x] Manually verified in `examples/v2/react`

Author: onsclom

docs/content/docs/reference/v2/hooks/useComponent.mdx

@@ -30,6 +30,7 @@ function useComponent<
     // When omitted, render accepts any props.
     render: ComponentType<InferRenderProps<TSchema>>;
     agentId?: string;
+    followUp?: boolean;
   },
   deps?: ReadonlyArray<unknown>,
 ): void;
@@ -42,6 +43,7 @@ function useComponent<
 - `config.parameters`: optional Zod schema for typed/validated parameters. When provided, `render` props are inferred from the schema.
 - `config.render`: React component rendered with parsed tool parameters. Accepts any props when `parameters` is omitted.
 - `config.agentId`: optional agent scope for the registration.
+- `config.followUp`: optional, defaults to `true`. Set `false` to suppress the agent's follow-up message after rendering.
 - `deps`: optional dependency array for refreshing registration.
 
 ## Behavior

packages/react-core/src/v2/hooks/__tests__/use-component.test.tsx

@@ -45,7 +45,7 @@ describe("useComponent", () => {
     );
   });
 
-  it("appends custom description and forwards parameters, agentId, and deps", () => {
+  it("appends custom description and forwards parameters, agentId, deps, and followUp", () => {
     const weatherSchema = z.object({
       city: z.string(),
       unit: z.enum(["c", "f"]),
@@ -65,6 +65,7 @@ describe("useComponent", () => {
           parameters: weatherSchema,
           render: DemoComponent,
           agentId: "weather-agent",
+          followUp: false,
         },
         deps,
       );
@@ -79,6 +80,7 @@ describe("useComponent", () => {
         description: string;
         parameters: typeof weatherSchema;
         agentId?: string;
+        followUp?: boolean;
       },
       ReadonlyArray<unknown>,
     ];
@@ -91,6 +93,7 @@ describe("useComponent", () => {
     );
     expect(toolConfig.parameters).toBe(weatherSchema);
     expect(toolConfig.agentId).toBe("weather-agent");
+    expect(toolConfig.followUp).toBe(false);
     expect(forwardedDeps).toBe(deps);
   });
 

packages/react-core/src/v2/hooks/use-component.tsx

@@ -65,6 +65,7 @@ export function useComponent<
     parameters?: TSchema;
     render: ComponentType<NoInfer<InferRenderProps<TSchema>>>;
     agentId?: string;
+    followUp?: boolean;
   },
   deps?: ReadonlyArray<unknown>,
 ): void {
@@ -83,6 +84,7 @@ export function useComponent<
         return <Component {...(args as InferRenderProps<TSchema>)} />;
       },
       agentId: config.agentId,
+      followUp: config.followUp,
     },
     deps,
   );